Induced transglottal pressure variations during voicing

The effect of variations in the transglottal driving pressure on the glottal air flow waveform is basic to the understanding of the functioning of the laryngeal sound source during speech. A number of laboratories have reported experimentally manipulating the transglottal pressure by mechanically varying the subglottal or supraglottal pressures. If the variations occur in about 100 msec or less it can be assumed that there were no significant compensatory changes in laryngeal or respiratory muscle activity. In this study the supraglottal pressure was varied by having the subject speak into a box having four 15‐in. loudspeakers in its walls. The loudspeakers generated variations in supraglottal pressure at preset points in the vocalization. The subject spoke through a circumferentially vented pneumotachograph mask which yielded the glottal air flow waveform after inverse filtering. Reported here are the first attempts at using this apparatus to map out the relationships between transglottal pressure, voice fundamental frequency, peak air flow during the glottal pulse, and glottal pulse width.