Course:PHYS341/2018/Calendar/Lecture 26
Phys341 Lecture 26: Summary and web references
2018.03.16
Textbook Ch.19.1-19.7
Brasswind
- Winds: classification (Table 18-1 in text)
- Mouthpiece
- Lip reeds
- Shapes
- The Bell
- The curvature of the bell has two effects:
- For low frequencies (long wavelengths) the end looks abrupt.
- Trumpet bore behaves acts as an open tube.
- Sound waves reflected back into the tube from the end.
- Supports standing waves.
- For high frequencies (short wavelengths), the transition from tube to open air is so gentle that the sound waves do not notice the change.
- Trumpet bore behaves like an infinitely long tube.
- No reflections at end.
- Does not support standing waves.
- Mellow sound
- Reflections
- The variable length of the standing wave allows players to vary the pitch of the notes played.
- Makes it harder to play in tune.
- Horn players use their hands to vary the effective length of the pipe.
- B♭ trumpet
- Changing tube length: valves
- Trombone
- Changing tube length: slide
- Energy chain