Course:PHYS341/2018/Calendar/Lecture 26

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Phys341 Lecture 26: Summary and web references

2018.03.16

Textbook Ch.19.1-19.7

Brasswind

  1. Winds: classification (Table 18-1 in text)
  2. Mouthpiece
  3. Lip reeds
  4. Shapes
  5. 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
  6. 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.
  7. B♭ trumpet
    • Changing tube length: valves
  8. Trombone
    • Changing tube length: slide
  9. Energy chain