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Significance ofMouthpieces and
Headjoints in ToneProduction of WoodwindInstruments
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Woodwind Instruments
are aerophones
resonance is created by vibrationsin the air
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Mechanical Reed
A physical reed which oscillates
- these are usually made from a certaintype of grass native to Egypt
Instruments which have thismechanism are:
clarinet
bassoon
oboeImage: Bower, Michael, Woodwind family, CA, viewed 3 November 2010
,
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Air Reed Mechanism
Air jet which oscillates (like areed)
Instruments which use thismechanism:
flute
recorder
flageolet
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How do these create asound?The mouthpiece interacts with
the air column, like a feedbackloop:
the air pressure entering the aircolumn is varied by oscillation ofa mechanical/air reed
This creates a standing wave in theair column
The varying pressure in the aircolumn in turn acts as a force on
the reed
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Feedback Loop inWoodwinds
Ima e: (p401, Adachi, 2004)
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How does the mechanicalreed work?
1. Blowing into the mouthpiece initially creates apressure build-up
2. This higher pressure inside the mouthpiece forces
the reed(s) to open completely3. The pressure in the mouthpiece decreases back
to near-atmospheric pressure and the reedreturns to its original position
4. The pressure is below atmospheric and thereed closesIma e: (p260, Campbell & Greated, 1994)
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How an air reed works
- Blowing onto the labium splits the air jet comingfrom your mouth
- The jet becomes unstable and begins oscillating,
exciting the air column acoustically- A standing wave is set up in the tube andvariations in pressure in the tube then create anacoustic velocity which makes the jet oscillate evenmore
- With a proper air jet speed, its oscillations will beIma e: (p285, Campbell & Greated, 1994)
Air jetoscillationsin flute
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The Effect of theMouthpiece on HarmonicsThe end conditions provided by
the different mouthpieces willcreate either a pressure node or
antinode at the blowing end.A mechanical reed will act as aclosed end, an air reed will act
as an open endAt an open end the air is free to
flow in and out and the pressure
stays constant
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Harmonics of differentwoodwinds
This has an effect on the tonecolour of the instrument aninstrument open at both ends has aIma e: Wolfe, Joe, Open vs. Closed pipes, Australia, viewed 24 October 2010,
air reed instruments Mechanical reed
instruments
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Mechanical Reed andDynamicsThe dynamics of a reed
instrument are influenced by theamplitude of oscillation of the
reedAllowing for a greater amplitude
of oscillation in the reed
increases the dynamic level ofthe instrument
For quiet dynamics the musician
tightens his embouchure
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Air Reed,Dynamics and
PitchThe frequency of the note
played is related to the speed of
the air jet (v) and the distancefrom the end of the flue to thelabium (h)
As v/h rises, the frequency rises This means for higher notes v must
be larger, and we get an increase in
intensityIma e: (p.25, Nederveen, 1969)
Recordermouthpiece
labiumflue
air
jet
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Headjoints and tuning
Headjoints can be pulled in orout, to change the length of theair column and therefore the
pitch of the note for tuning
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References
Adachi, S. (2004, November 1). Principles of soundproduction in wind instruments.Acoustical Science andTechnology, 25, pp. 400-405.
Campbell, M., & Greated, C. (1994). Musician's Guide toAcoustics, The. Oxford University Press.
Howard, M. D., & Angus, J. (2009).Acoustics andpsychoacoustics. Oxford: Focal Press.
Nederveen, C. J. (1969).Acoustical Aspects of WoodwindInstruments. Amsterdam: Frits Knuf.
Smith, H. D. (1992). Reed Design for Early Woodwinds.Bloomington and Indianapolis: Indiana University Press.
Bower, Michael, Woodwind family, CA, viewed 3 November2010,http://www.empire.k12.ca.us/capistrano/Mike/capmusic/instrume.
Wolfe, Joe, Open vs. Closed pipes, Australia, viewed 24
http://www.empire.k12.ca.us/capistrano/Mike/capmusic/instruments/instruments.htmhttp://www.empire.k12.ca.us/capistrano/Mike/capmusic/instruments/instruments.htm