PercussionSlide 2Membranes modes of vibrationResonances of the membraneResonances of the drum vs that of the bodySlide 6Drum tuningSpectrum of a drumDrum ensemble from BeninFrame DrumGoblet Drum - DarbukaSpectrum of DarbukaTabla IndiaSteel pipeSteel pipe held at different locationsJew Harp (Rajasthan, moorchang)Lamellaphone –Sanza -west africaSlit Drum -central AfricaGuinea Bala XylophoneDouble pit xylophone Benin dosoStomping tubes-Solomon islandsAngklung-sliding rattle JavaGamelan – Bali – Metallophone EnsembleTopicsPercussionPhysics of Music PHY103PercussionDivided into •Membranophones: drums and •Ideophones: chimes, xylophones, marimbas, jawharps, boos, tongue drums, bells, gongsCould also be divided into those with pitch and those withoutMembranes modes of vibration•The first three modes C1,C2, C3 are axisymmetric (circular rings).•The last 2 modes have azimuthal structure (bilateral) L1, L2 •C vs L mode spectrum depends on where you hit the drum. You get higher frequency vibrations when you hit the edge of the drumC1 f1C2 2.3f1 sharp major 9thC3 3.6f1 octave + minor 7thL1 1.59f1 minor 6thL2 2.92 f1 octave + 5thResonances of the membrane•By changing the tension on the membrane you can change the pitch of the drum (experiment with flatdrum!)•By making the membrane heavier you should be able to lower the pitchResonances of the drum vs that of the body•A: frame drum•B: Tenor drum•C: Barrel drum with narrow opening•D: Barrel drum with large opening•E: tube drumResonances of the drum vs that of the body•A: No added resonance -- out of phase waves from front and back cancel•C: Membrane and barrel could have different resonances- barrel usually has a deeper tone than the drum head – narrow resonance peak for barrel•D: Barrel might have a wider resonance peakDrum tuning•Adjusting the tension of the drum head changes the resonant frequencies of the drum head•It also changes the resonant frequencies within the drum chamber --- this is because the rigidity of the walls affects these resonances•Process of adjustment required to have the resonances of the membrane reinforce the resonances of the drum body --- leading to a fuller soundSpectrum of a drumToca drum (mine)Drum ensemble from BeninSound box of wood with a laced skin membrane. The sound changes when stuck at different positions on the drum head.Frame Drum•Change from Rajasthan•One meter large, can be hit by more than one playerGoblet Drum - Darbuka•Egygt•Goblet with a glued membrane of lambskin•Tone quality is adjusted solely from changes of power and angle of attackSpectrum of DarbukaTabla India•Note vocalization following•membrane thickness varies so sound is very sensitive to position hitSteel pipe•Modes exited depend on where you hold itSteel pipe held at different locations•Note first overtone absent in green spectrumJew Harp (Rajasthan, moorchang)Lamellaphone –Sanza -west africaSlit Drum -central Africa•hollowed out wood with uneven thickness to the edgesGuinea Bala XylophoneDouble pit xylophone Benin doso•pit dug into the ground serves as a resonatorStomping tubes-Solomon islands•bamboo pipes striking a rockAngklung-sliding rattle JavaGamelan – Bali – Metallophone EnsembleTopics•Resonances/modes of a membrane•Modes of a vibrating pipe or bar•Modes of a resonating cavity coupled to a membrane•Membranophones/ideophones and lamellaphones•Suggested reading: Chapters x+x of
View Full Document
Unlocking...