UBC Wiki - User contributions [en]

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:23:06Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>.
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref name=Hillaire1971 />.

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />.

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />.

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:20:47Z

SheaOracheski: /* Harmonium */

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>.
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref name=Hillaire1971 />.

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />.

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:20:04Z

SheaOracheski: /* The Problem with Pitch Bending */

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards. <ref name=Hillaire1971 />

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />.

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:19:44Z

SheaOracheski: /* Decreasing Reed Chamber Volume */

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards. <ref name=Hillaire1971 />

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:19:25Z

SheaOracheski: /* Partial Pallet Opening */

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards. <ref name=Hillaire1971 />

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T21:15:35Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref name=Hillaire1971>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards. <ref name=Hillaire1971 />

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref name=Gellerman1997>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref name=Gellerman1997 />

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref name=Cottingham2011>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref name=Cottingham2013>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref name=Cottingham2013 />

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref name=Cottingham2013 />

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref name=Cottingham2011 />

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T20:12:19Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

In summary, pitch bending on a Harmonium is scientifically possible, but when it comes to the practicality, it can only be achieved in very minimal amounts through partial pallet opening, varying air pressure, and decreasing the reed chamber volume. This shows that the instrument's original design and purpose (sustained single notes) is very difficult to overcome.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T20:06:54Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|upright=3|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|left|upright=2|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T19:47:59Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Harmonium Free Reed Diagram.jpg|thumb|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

File:Harmonium Free Reed Diagram.jpg

2017-03-30T19:46:44Z

SheaOracheski: User created page with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement}}
|date=2017-03-30 12:46:07
|source={{own}}
|author=[[User:SheaOracheski|SheaOracheski]]
|permission=
|other_versions=
}}

=={{int:license-header}}==
{{self|cc-by-sa-3.0}}

[[Category:Uploaded with UploadWizard]]

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T19:45:45Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===
[[File:Free Reed Diagram|largepx|thumbnail|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

[[File:Free_Reed_Diagram.jpg#filelinks|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T19:30:54Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down. [[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium<big><big><big>===

[[File:Free Reed Diagram|thumbnail|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T18:59:52Z

SheaOracheski:

[[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[needs short intro before the contents box - CEW]

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down.

[[File:Free Reed Diagram|thumbnail|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

File:Free Reed Diagram.jpg

2017-03-30T18:51:23Z

SheaOracheski: User created page with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement}}
|date=2017-03-30 11:51:02
|source={{own}}
|author=[[User:SheaOracheski|SheaOracheski]]
|permission=
|other_versions=
}}

=={{int:license-header}}==
{{self|cc-by-sa-3.0}}

[[Category:Uploaded with UploadWizard]]

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T02:42:59Z

SheaOracheski:

[[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[needs short intro before the contents box - CEW]

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down.

[[File:Reed Diagram2.jpg|thumb|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement [use drawing program to create clearer diagram - CEW] ]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India. There it was adapted to be played while sitting on the ground, with the addition of a hand pump instead of pedals. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-30T02:36:25Z

SheaOracheski:

[[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[needs short intro before the contents box - CEW]

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down.

[[File:Reed Diagram2.jpg|thumb|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement [use drawing program to create clearer diagram - CEW] ]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by air produced by pressure bellows rather than suction bellows. Bellows are commonly operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump [hard to parse this sentence - CEW]. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies, or long notes <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch of the available notes by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve controls the airflow to the reeds and is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

[This section would be a lot easier to understand with a good well-labelled diagram of the whole instrument showing how all the parts fit together- CEW]

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

[Is this a conclusion section? - CEW]

==References==
{{reflist}}

Thread:User talk:Chris Waltham/Peer Review

2017-03-21T22:37:07Z

SheaOracheski: New thread: Peer Review

Hey, I found this to be a very interesting topic, and since I know almost nothing about synthesizers, it was also very informative. I think that for the most part it was written very well, except for a couple of lines where you switch over to persuasive/subjective instead of objective writing. For example the line "The infinite qualities of a modular synthesizer are what make its composition so unique, dynamic, and infinitely possible, depending on the preference of the player", has a lot of extra fat to it that isn't very helpful. All this sentence is telling us is that it creates a unique and customizable sound, so all the descriptors are sort of getting in the way. Other than that I thought the content was great!

The biggest thing for me was the lack of sources and the formatting of the page (which I'm sure you intend to work further on). So make sure you cite your sources, I would say that's pretty important. An awesome thing I learned from looking into the source code from the example page is a way to format your page into different categories and sub categories. For example, you have all of your subcategories labeled as 2a, 2b, 2c (etc.), but if you place '====' on either side of your title you can actually have them automatically create a subcategory! So look into the source code and you can find some other ways to make your page easier to navigate, like adding subcategories, a reference list, and a table of contents.

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-17T18:10:49Z

SheaOracheski:

[[Category:PHYS341-2017|example wiki project]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down.

[[File:Reed Diagram2.jpg|thumb|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T20:04:51Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating up and down.

[[File:Reed Diagram2.jpg|thumb|Figure 1: Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibrating. Top View: shaded area shows hole in the shallot plate beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Figure 2: Underside of a harmonium showing its scaled set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T19:59:37Z

SheaOracheski: /* Varying Air Pressure */

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram2.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Underside of a harmonium showing its set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>.

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T19:53:08Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram2.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:German Jubilate Harmonium Reeds.jpg|thumb|German Jubilate Harmonium Reeds|Underside of a harmonium showing its set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T19:49:43Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram2.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail|Underside of a harmonium showing its set of reeds from a Classic German instrument]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T19:27:22Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram2.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

File:Reed Diagram2.jpg

2017-03-14T19:26:13Z

SheaOracheski: User created page with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement}}
|date=2017-03-14 12:25:19
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[[Category:Uploaded with UploadWizard]]

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T19:24:57Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

[[File:Reed Diagram|thumbnail|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T18:24:19Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram.jpg|thumb|Diagram of a reed from a free-reed instrument sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.. Side view: dotted lines show movement of reed when vibratingTop View: shaded area shows hole beneath the reed allowing free movement]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

File:Reed Diagram.jpg

2017-03-14T18:22:14Z

SheaOracheski: User created page with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Diagram of a reed from a free-reed instrument.
Side view: dotted lines show movement of reed when vibrating
Top View: shaded area shows hole beneath the reed allowing free movement}}
|date=2017-03-14 11:20:57
|source={{own}}
|author=[[User:SheaOracheski|SheaOracheski]]
|permission=
|other_versions=
}}

=={{int:license-header}}==
{{self|cc-by-sa-3.0}}

[[Category:Uploaded with UploadWizard]]

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T18:20:39Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed Diagram|thumbnail|a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above. Both top view and side view. Dotted lines show movement direction of the reed in motion and shaded area shows the hole beneath the reed.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T18:10:51Z

SheaOracheski:

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed diagram.PNG|thumbnail|Figure 1: a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>.

[[File:Https://upload.wikimedia.org/wikipedia/commons/2/25/German Jubilate Harmonium Reeds.jpg|thumbnail]]
The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-14T17:59:23Z

SheaOracheski:

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed diagram.PNG|thumbnail|Figure 1: a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

====Varying Air Pressure====

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Partial Pallet Opening====

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

====Decreasing Reed Chamber Volume====

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-12T19:54:48Z

SheaOracheski:

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed diagram.PNG|thumbnail|Figure 1: a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

==Varying Air Pressure==

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Partial Pallet Opening==

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Decreasing Reed Chamber Volume==

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

==References==
{{reflist}}

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-12T19:51:40Z

SheaOracheski:

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed diagram.PNG|thumbnail|Figure 1: a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies <ref>Gellerman, Robert F. The American Reed Organ. 2nd ed. N.p.: Vestal, 1997. Print.</ref>.

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

==Varying Air Pressure==

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Partial Pallet Opening==

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Decreasing Reed Chamber Volume (page 92 american organ)==

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-03-12T19:35:45Z

SheaOracheski: /* Harmonium Pitch Bending */

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

[https://en.wikipedia.org/wiki/Pump_organ#Acoustics Harmoniums] are a part of the Free-Reed instrument family, along with harmonicas, pump-organs, and accordions. The reed is a small metal strip that is fastened at one end and free at the other. The free end sits above a hole that is just big enough for the reed to be able to pass through when vibrating.

[[File:Reed diagram.PNG|thumbnail|Figure 1: a single reed sitting on a shallot plate where the hole underneath the reed is slightly larger than the reed above.]]

In a harmonium there is a different reed for every key on the keyboard, and separate divided columns for each reed <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. Unlike the organ however, the reeds within the instrument are excited by pressure bellows rather than suction bellows that can be operated by pedals on the floor in Western harmoniums, and by a hand pump in different Eastern variations <ref>Earl, S. G. Repairing the Reed Organ and Harmonium. Braintree: Organ Literature Foundation, 1960. HathitTrust. Web. 5 Mar. 2017.</ref>. This means that there needs to be a large amount of air produced and pushed past all the reeds in order to produce sound from multiple keys at once. Air passing the reeds excites them into vibrating which creates the sound of the harmonium. In most western free-reed instruments the reed sits on top of a plate with a hole in it that allows air to escape and pressure to decrease when the reed is forced downwards <ref>
Hilaire, Arthur O. St, Theodore A. Wilson, and Gordon S. Beavers. "Aerodynamic Excitation of the Harmonium Reed." Journal of Fluid Mechanics 49.04 (1971): 803-16. University of British Columbia Library. Web. 5 Mar. 2017</ref>. The actual sound that is produced is a result of two conjoining forces. The vibration of the reed itself creates sound through its resonating body on the soundboard that is the heart of the harmonium. The second is the periodic stutter of air that is released through the reed as it vibrates, contributing to the timbre of the instrument. (American reed organ).

The harmonium’s initial design was to create long lasting single notes that were achieved by the mechanically generated pressure forcing its way past the reeds. Commonly this was produced in the form of foot pedals, and then adapted as the instrument was adopted in India and adapted to be played while sitting on the ground with a hand pump. Either way, it was not designed to create wavering melodies, it was meant for sustained frequencies. (the American reed organ)

===<big>Achieving Pitch Bending<big>===

When playing a harmonica, experienced musicians can control pitch by varying the amount of air they force through the instrument as well as controlling their vocal tract (the resonator of the harmonica). This is not as easily achieved with a harmonium, or any other free-reed instrument, because the air flow is mechanically operated <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>. Even though it is more difficult, it isn’t impossible, and the same techniques apply to pitch bending a harmonium.

==Varying Air Pressure==

Varying the amount of air pressure being forced through the valves of a harmonium can change the frequency in which the reed vibrates, which will change the pitch of the instrument. This is achieved by either pushing the pedals or pumping the hand pump harder and more frequently. When pressure is increased in a free-reed instrument, the frequency (somewhat counterintuitively) decreases. This is because the pressure being applied to the reed becoming stronger results in the reed staying in its downward position longer, reducing frequency <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Partial Pallet Opening==

The pallet valve is attached to the key on the keyboard, and when the key is pressed, the valve opens, allowing air to flow past the reed. This has a very similar effect as the varying air pressure because it’s doing the same thing in a different way. By depressing the key at different levels the amount of air that is passing the reed is changing, which will impact the frequency at which the reed vibrates. In fact, the less depressed the key is, the greater the frequency is capable of changing. Also comparable to the varying pressure technique is that the frequency decreases when the keys are less depressed. This is due to the fact that less air is entering the reed cell meaning the reed itself is not being excited as much, causing it to vibrate less <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

==Decreasing Reed Chamber Volume (page 92 american organ)==

The Reed Chamber is area of space in which the reed sits, and where air pressure accumulates once it is being forced past the reed. By decreasing the size of the reed chamber, more air is able to accumulate quicker when it passes the reed, meaning there is more pressure on the opposite side of the reed pushing it back. This causes the pressure to even out on either side of the reed, resulting in a decrease in frequency of the reed. In fact this has the greatest effect of the three techniques, however in a classical harmonium there is no built in adjustment feature that allows the user to change this parameter, so it can only be achieved by modifying the instrument <ref>Cottingham, James P. Reed Vibration and Pitch Bending in Western Free Reed Instruments. Stanford: Stanford University, 15 Feb. 2013. PPT.</ref>. (cottingham) graph

===<big>The Problem with Pitch Bending<big>===

There is one main issue in pitch bending a harmonium because of its free reed system. The free reed system requires a base level of energy to excite each individual reed into vibration, and if there is not enough energy being put into the system, no sound will be created. Inversely, if there is too much energy being forced past the reed, then the material’s own restoring force is not enough to combat the wind pushing against it, causing the reed to vibrate less. This means that although it is possible to bend the pitch of a free reed instrument with a mechanically operated air vent, it can only be done in very slight amounts. Amounts so small that it is almost negligible when brought in context of a musical piece. The only way to allow for further pitch bending is to increase the resonating cavity, which is common for organs with large stacks of resonating pipes <ref>Cottingham, James P. "Acoustics of Free-Reed Instruments." Physics Today 64.3 (2011): 44-48. Physics Today. American Institute of Physics, 2011. Web. 5 Mar. 2017.</ref>.

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-02-15T19:43:46Z

SheaOracheski:

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

===<big><big><big>Harmonium Pitch Bending<big><big><big>===

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-02-15T19:39:23Z

SheaOracheski:

[[Category:PHYS341-2017|Harmonium Pitch Bending]]

<big><big><big>Harmonium Pitch Bending<big><big><big>

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-02-15T19:33:43Z

SheaOracheski:

<big><big><big>Harmonium Pitch Bending<big><big><big>

Course:PHYS341/Archive/2016wTerm2/HarmoniumPitchBending

2017-02-15T19:33:26Z

SheaOracheski: Created page with "<big>Harmonium Pitch Bending<big>"

<big>Harmonium Pitch Bending<big>

User:SheaOracheski

2017-02-15T19:28:35Z

SheaOracheski:

Shea Oracheski

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2017-02-15T19:27:43Z

SheaOracheski: Blanked the page

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2017-02-15T19:26:44Z

SheaOracheski: Created page with "Harmonium Pitch Bending"

Harmonium Pitch Bending

Course:PHYS341/Archive/2016wTerm2/Wiki project ideas

2017-02-01T18:29:52Z

SheaOracheski:

'''Topic must be about the Physics of MUSIC, not just the physics of sound.''' 
Chris Waltham "How does the choice of wood affect the sound of a Persian santur?" 
M. Pourian, https://manusantur.wordpress.com/ and Journal of Acoustic Woods, '''37''' (2016) p.239. 

-------------------------------------------------------------------------------------------------------------------------
Jonathan Kwok "Orchestra members' effect on sound absorption and reflection in concert hall setting" 
http://asa.scitation.org.ezproxy.library.ubc.ca/doi/pdf/10.1121/1.4971763 
-------------------------------------------------------------------------------------------------------------------------
Shea Oracheski "How would one create a pitch bending effect in a harmonium"

https://ccrma.stanford.edu/courses/318/mini-courses/Winter2013/Cottingham-2.pdf
https://www.youtube.com/watch?v=C0t1f-N3e2U
-------------------------------------------------------------------------------------------------------------------------
Alfred Ko "How do a violin's f-holes contribute to its sound?" 
http://web.b.ebscohost.com/ehost/detail/detail?vid=1&sid=d8fc2370-2bfa-4beb-9245-bf55caf2d61c%40sessionmgr102&hid=128&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#AN=4299280&db=a9h

Beament, James, and Dennis Unwin. "The Hole Story." Strad 112.1332 (2001): 408. Academic Search Complete. Web. 30 Jan. 2017.
-------------------------------------------------------------------------------------------------------------------------
Andrea Wong "How does the soundpost contribute to a string instrument's sound?"
https://www.researchgate.net/profile/George_Bissinger/publication/241390846_The_Influence_of_the_Soundpost_on_the_Mechanical_Motions_of_the_Violin/links/5792486608aec89db781bf34.pdf
-------------------------------------------------------------------------------------------------------------------------
Tina Cheung "The affect of singing frequency on the resistance of glass?"

https://www.scientificamerican.com/article/fact-or-fiction-opera-singer-can-shatter-glass/
-------------------------------------------------------------------------------------------------------------------------
Diana Gil "How does the construction of a semi-hollow guitar affect the acoustics of the instrument?"

Acoustics of Guitars - Thomas D. Rossing - http://asa.scitation.org/doi/abs/10.1121/1.412720

Fundamentals of Guitar Tone - Erik V. Jansson - DOI: http://dx.doi.org/10.1121/1.2019626

Solidbody or Hollowbody ... Which is right for me?- Russell Hall - http://www.gibson.com/news-lifestyle/features/en-us/solidbody-or-hollowbody-guitar-0829-2012.aspx

Investigating the Effect of Body Geometry on the Acoustics of Electric Guitars - Mark Rau and Gary Scavone - http://asa.scitation.org/doi/10.1121/1.4950571

Engineering the Guitar: Theory and Practice - Richard Mark French
http://link.springer.com.ezproxy.library.ubc.ca/book/10.1007/978-0-387-74369-1
-------------------------------------------------------------------------------------------------------------------------
Shaula Wong "Relative Humidity and its Affect on Live Music" 
https://ccrma.stanford.edu/~jos/HarrisJASA66.pdf 
-------------------------------------------------------------------------------------------------------------------------
Matt Papadopoulos "Effects of reverberation inside the Dan Harpole Cistern at Fort Worden State Park, WA" 
http://www.newmusicbox.org/articles/cistern-chapel/ 
https://www.youtube.com/watch?v=oZ8MhEn-jm4 
-------------------------------------------------------------------------------------------------------------------------
Cody Wisniewski "The limitations of the structural design in the Sydney Opera House in Sydney, NSW, Australia effects on the quality of performance's acoustics and evaluation of proposed renovations"

Investigations of stage acoustics at the Sydney Opera House Concert Hall - DOI: http://dx.doi.org.ezproxy.library.ubc.ca/10.1121/1.3654688 - Timothy E. Gulsrud (Oct 2011)
http://www.telegraph.co.uk/news/2016/08/11/sydney-opera-house-announces-major-renovations-to-fix-its-hideou/ - Proposed Changes (Aug 2016)

------------------------------------------------------------------------------------------------------------------------
Pei-tong Lin "The effect of the vocal tract on the tune of woodwind instruments"
 http://asa.scitation.org/doi/abs/10.1121/1.392556 
-------------------------------------------------------------------------------------------------------------------------

Next person "Next topic" 
Reference to scholarly work (print or URL) - at least one good one

Course:PHYS341/Archive/2016wTerm2/Wiki project ideas

2017-01-30T19:29:01Z

SheaOracheski:

Chris Waltham "How does a violin's scroll contribute to its sound?" 
https://newt.phys.unsw.edu.au/music/people/mclennan/McLennanThesisComplete.pdf 
Section 10.4 The Effect of Neck/Scroll Mass and Chinrest on Body Modes. 
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Jonathan Kwok "Temperature's effect on various soundwaves & frequencies underwater" 
http://asa.scitation.org/doi/10.1121/1.4946898 
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Shea Oracheski "How does the temperature of a material affect its absorbing potential"

http://nvlpubs.nist.gov/nistpubs/jres/9/jresv9n2p175_A2b.pdf
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Next person "Next topic" 
Reference to scholarly work (print or URL) - at least one good one

Course:PHYS341/Archive/2016wTerm2/Wiki project ideas

2017-01-30T19:28:42Z

SheaOracheski:

Chris Waltham "How does a violin's scroll contribute to its sound?" 
https://newt.phys.unsw.edu.au/music/people/mclennan/McLennanThesisComplete.pdf 
Section 10.4 The Effect of Neck/Scroll Mass and Chinrest on Body Modes. 
-------------------------------------------------------------------------------------------------------------------------
Jonathan Kwok "Temperature's effect on various soundwaves & frequencies underwater" 
http://asa.scitation.org/doi/10.1121/1.4946898 
-------------------------------------------------------------------------------------------------------------------------
Shea Oracheski "How does the temperature of a material affect its absorbing potential"
http://nvlpubs.nist.gov/nistpubs/jres/9/jresv9n2p175_A2b.pdf
-------------------------------------------------------------------------------------------------------------------------
Next person "Next topic" 
Reference to scholarly work (print or URL) - at least one good one