Physics 1251 The Science and Technology of Musical SoundPhysics 1251 Unit 3 Session 30 The Timbre of Wind InstrumentsSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Physics 1251 Unit 3 Session 30 The Timbre of Wind InstrumentsSlide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Physics 1251Physics 1251The Science and The Science and Technology of Musical Technology of Musical SoundSoundPhysics 1251Physics 1251The Science and The Science and Technology of Musical Technology of Musical SoundSoundUnit 3Unit 3Session 30 MWFSession 30 MWFThe Timbre of Wind The Timbre of Wind Instruments Instruments Unit 3Unit 3Session 30 MWFSession 30 MWFThe Timbre of Wind The Timbre of Wind Instruments InstrumentsPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsWhat is the physical difference What is the physical difference between a Cornet, Trumpet and between a Cornet, Trumpet and Flugel Horn?Flugel Horn?CornetTrumpetTrumpetFlugel HornThe fraction of the horn The fraction of the horn that is that is cone/cylinder/flare.cone/cylinder/flare.• • Trumpet – most Trumpet – most cylindricalcylindrical• • Cornet -- more Cornet -- more conicalconical• • Flugel Horn – most Flugel Horn – most conicalconicalPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstruments11′ Lecture:′ Lecture:•The pitch of a wind instrument is determined by the The pitch of a wind instrument is determined by the length and shape of its air column.length and shape of its air column.•The effective length of the air column is controlled The effective length of the air column is controlled with holes, valves and slides.with holes, valves and slides.•Feedback from the resonances of the pipe select Feedback from the resonances of the pipe select the frequency of oscillation of the jet, reed or lip-the frequency of oscillation of the jet, reed or lip-valve.valve.•The excitation, transmission and emittance of the The excitation, transmission and emittance of the sound in the horn determine the timbre of the sound in the horn determine the timbre of the instrument.instrument.Physics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsTransverse FluteTransverse Flute80/2080/20The flute is driven by air flow against the The flute is driven by air flow against the edge of the embrochure hole.edge of the embrochure hole.80/2080/20A pressure node exists at the open hole.A pressure node exists at the open hole.EmbrochureEmbrochureAir Air flowflowPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsThe Single Reed The Single Reed 80/2080/20The reed opens and closes like a valve, The reed opens and closes like a valve, pressurizing the pipe when open, closing pressurizing the pipe when open, closing due to the Bernoulli effect when the air due to the Bernoulli effect when the air flows.flows.80/2080/20A pressure anti-node exists at the reed.A pressure anti-node exists at the reed.Air Air flowflowReedReedTonguingTonguingPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsThe Double Reed The Double Reed 80/2080/20The reed opens and closes like a valve, The reed opens and closes like a valve, pressurizing the pipe when open, closing pressurizing the pipe when open, closing due to the Bernoulli effect when the air due to the Bernoulli effect when the air flows.flows.80/2080/20A pressure anti-node exists at the reed.A pressure anti-node exists at the reed.Air Air flowflowReed TipReed TipPressure Pressure PulsesPulsesPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsThe Lip ValveThe Lip Valve80/2080/20Brass instruments are played by the Brass instruments are played by the player’s lips that form a lip valve. player’s lips that form a lip valve. 80/2080/20A pressure anti-node exists at the player’s A pressure anti-node exists at the player’s lips.lips.Louis Armstrong – Louis Armstrong – trumpet (1901-trumpet (1901-1971)1971)Physics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsComparison of Wind InstrumentsComparison of Wind InstrumentsBrassBrassffPedaPedal l ToneToneOther Other Woodwinds Woodwinds ClarinetClarinetFluteFluteff112f2f113f3f114f4f115f5f11ff113f3f115f5f115f5f11ff112f2f113f3f114f4f116f6f11ff11 = v/2L = v/2Lff11 = v/4L = v/4Lff11 = = v/2(L+c)v/2(L+c)LLcc ffoo = = (1+(1+ξξ)v/4(L+)v/4(L+c)c)ff11ffOO2f2fOO3f3fOO4f4fOO5f5fOO6f6fOOPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstrumentsComparison of Wind Instruments Comparison of Wind Instruments (cont’d.)(cont’d.)BrassBrassOther Other Woodwinds Woodwinds ClarinetClarinetFluteFluteff11 = v/2L = v/2Lff11 = v/4L = v/4Lff11 = = v/2(L+c)v/2(L+c)LLcc ffoo = = (1+(1+ξξ)v/4(L+)v/4(L+c)c)Open Open CylindCylinder Ner Npp – – NNppffnn = = nfnf1 1 ff11 = = v/2Lv/2L Stopped Stopped Cylinder Cylinder A App – N – Npp f f2n-12n-1 = = (2n-1)f(2n-1)f11 f f11= = v/4Lv/4LStopped Stopped Cone Cone AApp – N – Np p f fnn = nf = nf11 f f11= = v/2(L+c)v/2(L+c)Stopped Stopped CombinatiCombination on AApp – N – Np p f fnn = nf = nf00 ff00= = (1+(1+ξ)ξ)v/4(L+cv/4(L+c))Physics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstruments80/2080/20In the flute, feedback from the acoustic In the flute, feedback from the acoustic standing wave locks the frequency of the standing wave locks the frequency of the oscillation if the edge tone is near the oscillation if the edge tone is near the fundamental frequency.fundamental frequency.Displacement Displacement wavewaveffedgeedge = 0.2 v = 0.2 vjetjet /b /b ffnn = n v/ 2L; f = n v/ 2L; fedgeedge ≈ f≈ fnnPhysics 1251Physics 1251Unit 3 Session 30Unit 3 Session 30 The Timbre of Wind The Timbre of Wind InstrumentsInstruments80/20I80/20IIn reed instruments, feedback from the In reed instruments,