A physiological and acoustic study on voiced bilabial fricative/beta:/as a vocal exercise.

The voiced bilabial fricative/beta:/has been used as a vocal exercise. The present study investigated the effects of the exercise on voice production and voice source. This study compared vowel phonation on the syllable /a:p/ with the production of the exercise and vowel phonation before and immediately after the exercise. The methods were (a) dual-channel electroglottography, from which the vertical laryngeal position was derived, (b) electromyography using surface electrodes, and (c) inverse filtering of the acoustic signal to obtain an estimate of the voice source. In the production of /beta:/ as compared with vowel phonation in most of the cases, the vertical laryngeal position seemed to be higher, the muscular activity of the larynx lower, and the slope of the voice source spectrum steeper. In vowel phonation after the exercise, the muscular activity seemed to be lower in most cases, although the voice source remained unchanged. This seems to indicate improved vocal economy.