Vocal loudness and effort in continuous speech.

Abstract

The direct-magnitude-estimation scaling technique was used to investigate listener perception of vocal loudness and vocal effort of a continuous speech sample. Three experimental conditions were developed that represented (1) normal changes in loudness and effort, (2) intensity held constant and effort varied, and (3) intensity varied and effort constant. The speech samples were judged by 20 listeners on the magnitudes of loudness and of the amount of effort used by the speaker during phonation. Exponents of the loudness and effort functions (1.12 and 0.57, respectively) suggest that vocal loudness and effort are different percepts of the listener. An examination of the acoustic stimuli suggests that a systematic increase in stimulus bandwidth with an increase in vocal intensity may be related to judgments of both loudness and effort.