PHY2464 - The Physical Basis of Music PHY-2464 Physical Basis of Music PHY PHY- 2464 2464 Physical Basis of Music Physical Basis of Music Presentation 17 Brass Instruments Adapted from Sam Matteson’s Unit 3 Session 29 Sam Trickey Mar. 13, 2005 Presentation 17 Presentation 17 Brass Instruments Brass Instruments Adapted from Sam Matteson’s Unit 3 Session 29 Sam Trickey Mar. 13, 2005 PHY PHY-2464 2464 Pres. 17 Brass Instruments Pres. 17 Brass Instruments Brass instruments: Brass instruments: • Characterized by “buzzing” the lips in a mouth piece Characterized by “buzzing” the lips in a mouth piece • KEY FACT KEY FACT – Pipe is Pipe is closed closed at at mouthpiece mouthpiece end end to an excellent to an excellent approximation approximation • There are There are valved valved and and valveless valveless brass instruments brass instruments • There are “brasses” made with little or no metal. There are “brasses” made with little or no metal.
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PHY-2464 Physical Basis of Music - University of Florida · PHY-2464 Physical Basis of Music PHY-2464 Presentation 17 Brass Instruments Adapted from Sam Matteson’s Unit 3 Session
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PHY2464 - The Physical Basis of Music
PHY-2464Physical Basis of Music
PHYPHY--24642464Physical Basis of MusicPhysical Basis of Music
Brass instruments: Brass instruments: •• Characterized by “buzzing” the lips in a mouth pieceCharacterized by “buzzing” the lips in a mouth piece
•• KEY FACT KEY FACT ––Pipe is Pipe is closedclosed atat mouthpiecemouthpiece endend to an excellent to an excellent approximationapproximation
••There are There are valvedvalved and and valvelessvalveless brass instrumentsbrass instruments••There are “brasses” made with little or no metal.There are “brasses” made with little or no metal.
Brass InstrumentsBrass Instruments•• The lips produce a pulsation in the The lips produce a pulsation in the pressurepressure
admitted to the pipe. The pressure standing admitted to the pipe. The pressure standing wave feeds back to control oscillations of the wave feeds back to control oscillations of the playerplayer’’s lips.s lips.
The Lip ValveThe Lip ValveBrass instruments are played by the playerBrass instruments are played by the player’’s lips. s lips.
Breath pressure, muscle tension, and pressure feedback Breath pressure, muscle tension, and pressure feedback from the pipe determine the frequency of the opening and from the pipe determine the frequency of the opening and closing of the lips.closing of the lips.
Louis Armstrong Louis Armstrong –– trumpet trumpet (1901(1901--1971)1971)
•• The lips of the player act as a valve that admits The lips of the player act as a valve that admits pressure pulses into the pipe.pressure pulses into the pipe.
•• The frequency is determined by the breath air The frequency is determined by the breath air pressure, the lip tension and the resonances of pressure, the lip tension and the resonances of the pipe.the pipe.
Brass Instruments Brass Instruments are stopped pipes.are stopped pipes.
•• The playerThe player’’s lips s lips produce a displacement produce a displacement node (pressure node (pressure antinodeantinode) ) at the mouthpiece.at the mouthpiece.
•• A displacement antiA displacement anti--node node (pressure node) exists at (pressure node) exists at the bell.the bell.
The elements of a The elements of a valvelessvalveless brass instrument are brass instrument are illustrated by the illustrated by the HosaphoneHosaphone™™
The The cup volumecup volume and and the the diameter diameter of the of the constriction leading to constriction leading to the back bore are more the back bore are more important than the important than the shape of the cavity.shape of the cavity.
Resonances for Combination Bores in Resonances for Combination Bores in Brass InstrumentsBrass Instruments
Key FACT: A 50% cylindrical Key FACT: A 50% cylindrical -- 50% conical 50% conical bore has a nearly harmonic series.bore has a nearly harmonic series.
Various instruments Various instruments have different lengths have different lengths of cylindrical and of of cylindrical and of conical pipe.conical pipe.
SummarySummary•• Brass instruments are stopped pipesBrass instruments are stopped pipes•• The pipe bore is a combination of cylindrical and The pipe bore is a combination of cylindrical and
conical or flared, designed to give resonances conical or flared, designed to give resonances that are harmonic.that are harmonic.
•• Brass instruments are excited by lipBrass instruments are excited by lip--valves. valves. •• The playerThe player’’s lips are a soft reed.s lips are a soft reed.•• The pitch is determined by feedback from the The pitch is determined by feedback from the
resonances of the pipe.resonances of the pipe.•• The pitch is changed by exciting various The pitch is changed by exciting various
overtones and by changing the length of the pipe.overtones and by changing the length of the pipe.