Acoustic effects of variation in vocal effort by men, women and children
Journal of the Acoustical Society of America 107 (2000): 3438-3451
The acoustic effects of the adjustment in vocal effort that is required when the distance between speaker and addressee is varied over a large range (0.3-187.5 m) were investigated in phonated and, at shorter distances, also in whispered speech. Several characteristics were studied in the same sentence produced by men, women, and 7 year-old boys and girls: duration of vowels and consonants, pausing and occurrence of creaky voice, mean and range of F0, certain formant frequencies (F1 in [a] and F3), SPL of voiced segments and [s], and spectral emphasis. In addition to levels and emphasis, vowel duration, F0, and F1 were substantially affected. "Vocal effort" was defined as the communicational distance estimated by a group of listeners for each utterance. Most of the observed effects correlated better with this measure than with the actual distance, since some additional factors affected the speakers’ choice. Differences between speaker groups emerged in segment durations, pausing behavior, and in the extent to which the SPL of [s] was affected. The whispered versions are compared with the phonated versions produced by the same speakers at the same distance. Several effects of whispering are found to be similar to those of increasing vocal effort.