Significance of Mouthpieces and Head Joints in Tone Production

8/2/2019 Significance of Mouthpieces and Head Joints in Tone Production

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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

,
http://www.empire.k12.ca.us/capistrano/Mike/capmusic/instruments/instruments.htm


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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

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Significance of Mouthpieces and Head Joints in Tone Production