Abstract:

Subglottal pressure (P[inf s]) is the main variable for control of vocal loudness. Measuring its effects on the glottal voice source is complicated, since independent variation of voice control variables is typically difficult for untrained subjects. Professional singers, however, can be assumed to have learned such independent variation. The voice source was analyzed by inverse filtering of the flow signal in five professional operatic baritone singers who, at three pitches, sang a string of [pV:] syllables while performing a diminuendo. Subglottal pressure was measured from the oral pressure during the [p] occlusion. From the flow glottograms the following parameters were determined: Q[inf cl] (closed quotient), dU/dt (negative peak amplitude of the differentiated flow glottogram), glottal leakage, ac flow (peak-to-peak flow amplitude), H1--H2 (level difference between the two lowest spectrum partials), and glottal compliance (ratio pulse airflow to subglottal pressure). In all subjects, the effect of P[inf s] was similar and systematic for all parameters except glottal leakage. With decreasing P[inf s], ac flow and dU/dt decreased continuously while compliance increased and H1-H2 and Q[inf cl], showing a strong negative correlation, saturated at about 5 dB and 0.5, respectively. The results will be compared to findings from earlier investigations of untrained voices.