Singers change vocal pitch only via fold stiffness and vibrating mass

Evidence

Vocal fold vibration in a healthy larynx is a cyclic sequence in which the vocal folds close and open regularly when a note is being sung. Thus the vocal folds of a soprano singing A4 (f0  440.0 Hz) will complete this vocal fold closing and opening sequence 440 times a second. Singers have two methods by which they can change the f0 of vocal fold vibration: they alter the stiffness of the folds themselves by changing the tension of the fold mus­ cle tissue, or by altering the vibrating mass by sup­ porting an equal portion of each fold in an immobile position. Adjustments of the physical properties of the folds themselves allow many trained singers to sing over a pitch range of well over two octaves. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1340

Vocal fold vibration in a healthy larynx is a cyclic sequence in which the vocal folds close and open regularly when a note is being sung. Thus the vocal folds of a soprano singing A4 (f0 = 440.0 Hz) will complete this vocal fold closing and opening sequence 440 times a second. Singers have two methods by which they can change the f0 of vocal fold vibration: they alter the stiffness of the folds themselves by changing the tension of the fold muscle tissue or by altering the vibrating mass by supporting an equal portion of each fold in an immobile position. Adjustments of the physical properties of the folds themselves allow many trained singers to sing over a pitch range of well over two octaves. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1324

Categorization

• XREF: The stiffness/mass pitch-control duality parallels the frequency-control mechanisms of string and membrane instruments covered earlier in this chapter.
• DEFINE: Clarifies the two physiological mechanisms for altering vocal fold fundamental frequency.
• corroborated: 2 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1340; David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1324