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Phonation threshold pressure: A missing link in glottal aerodynamics
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1992
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AeroacousticsMinimum Lung PressurePsychoacousticsEngineeringKinesiologyPhonatory AerodynamicsPhoneticsNoisePhonation Threshold PressureHealth SciencesLarynxUltrasoundCavitating FlowAerospace EngineeringPhysiologyAerodynamicsPhonationSpeech PerceptionLung Pressure
Phonation threshold pressure has been defined as the minimum lung pressure required to initiate phonation. Glottal impedance for time‑varying flow should be defined differentially rather than as a simple ratio between lung pressure and peak flow, and singers’ data are compared with nonsingers to examine this relationship. Modeling shows that phonation threshold pressure depends on fundamental frequency, yielding simple aerodynamic relations, and that lung pressure and peak glottal flow are nearly linear but not proportional, so traditional power‑law vocal‑power relations may fail; moreover, peak flow, its derivative, open quotient, and speed quotient all depend on phonation threshold pressure, and singers achieve two to three times higher peak flow at the same lung pressure, indicating they adjust glottal or vocal‑tract impedance for optimal flow transfer.
Phonation threshold pressure has previously been defined as the minimum lung pressure required to initiate phonation. By modeling the dependence of this pressure on fundamental frequency, it is shown that relatively simple aerodynamic relations for time-varying flow in the glottis are obtained. Lung pressure and peak glottal flow are nearly linearly related, but not proportional. For this reason, traditional power law relations between vocal power and lung pressure may not hold. Glottal impendance for time-varying flow should be defined differentially rather than as a simple ratio between lung pressure and peak flow. It is shown that the peak flow, the peak flow derivative, the open quotient, and the speed quotient of inverse-filtered glottal flow waveforms all depend explicitly on phonation threshold pressure. Data from singers are compared with those from nonsingers. The primary difference is that singers obtain two to three times greater peak flow for a given lung pressure, suggesting that they adjust their glottal or vocal tract impedance for optimal flow transfer between the source and the resonantor.