7 Acoustics

AcousticsVowelAcousticsSoundenergy–vibratingvocalfoldsResonances=formants!Formants–changewithchangesinarticulatorsSpectrogram•Formants–seenasbandsofenergy.•Spectrogram–threedimensional.•Time–horizontal(lefttoright)•Frequency–vertical(toptobottom)•Intensity–degreeofblackness(gray-scale)Twotypes•Wideband–300Hzfilter–courseresolutionoffrequency.•Narrowband–45Hzfilter–fineresolutionoffrequency.•Hertz–cyclespersecond.•500Hz=500cyclespersecond(0.002sor2ms),1000Hz=1000cyclespers(0.001sor1ms).Whichspectrogramtouse?•Harmonics–narrowband.•Formants–wideband(eachformantgoesacrossacoupleofharmonics)•Formants–determinedbylength&shapeofvocaltract.F1=tongueheight,F2=tongueadvancement.•FundamentalFrequency–determinedbylength&tensionofvocalfolds.•#4iftheaverageF2frequencyforaparticularvowelis2000Hzforadultmalespeakers,what’stheexpectedaveragevalueforadultfemalespeakers?•Answer–about20%higher….So2400Hz!ConsonantAcoustics•SourceofEnergy–voicedhavevoicingpulsesrelatedtovibratingvocalfolds.Voicelessdonothavevoicingpulses!•VL–energyfromfrictionorburst.VOT•VoiceOnsetTime–timebetweenreleaseofstopclosureandonsetofvocalfoldvibration.•VOTforvoicedconsonants–lessthan20ms.•VOTforvoicelessconsonants–between30to80ms.•#5–TheVOTforword-initialstopsvarieswithseveralfactors.VOTislongerforvelarsthanalveolarandlongerforalveolarsthanbilabials.VOTislongerforVLthanvoiced.VOTislongerforstopsfollowedbyliquidsthanforsingletonstops.•Par,goat,boat,car,blusAnswer•Boat,Goat,Glue,Par,CarPlaceofConstriction•Formanttransitions–relatedtochangeinplaceofarticulation•Burstandfricationspectra–relatedtoplaceofconstriction.