Influence of Loudness on Vocal Stability in the Male Passaggio

Vocal registers and the frequency region where registration events occur, the passaggio, have been in focus of scientific research for almost 200 years. In professional tenors, it has been shown before that singing across the passaggio avoiding a register shift and therefore using their stage voice above the passaggio (SVaP) is associated with greater vocal stability than a register change to the falsetto. However, it is unclarified how much different loudness conditions contribute to this vocal stability.

Six professional tenors were asked to perform four pitch glides from A3 to A4 (220-440 Hz) on the vowel [i:]. These glides included (1) the passaggio from modal register to falsetto. The following glides into SVaP were performed under different loudness conditions, (2) mezzoforte (average loudness), (3) pianissimo (as quietly as possible), and (4) fortissimo (the loudest possible). During phonation, high speed videoendoscopy (HSV), electroglottography, and audio signals were recorded simultaneously. The glottal area waveform was derived based on the HSV material.

Modal to falsetto transitions were associated with relatively low sound pressure level and rise of open quotients (OQ) for the falsetto. Transitions to SVaP showed a clear dependence on the intended loudness. The OQs were lower the louder the task was. There was no clear evidence that transitions with softer voice showed greater stability of vocal fold oscillation patterns than louder tasks.

The vocal fold oscillation pattern show- differences among various loudness conditions within the tenors' passaggio but no clear differences with regard to oscillatory stability.