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This study was designed to investigate the formant frequencies and amplitudes of phonated and whispered productions of five test vowels (/i/, /u/, /æ/, /ɑ/, and /ʌ/). Each test vowel was sustained six times in isolation, three times in whisper and three times in phonation, by 15 adult male subjects. The phoneme represented by each recorded production was identified independently by 11 listeners. An acoustic spectrum of each sample was obtained through the use of a real-time narrow-band spectrum analyzer to permit formant measurements. This report presents the formant frequencies and amplitudes (F1to F3) of the test productions as measured from the acoustic vowel spectra and the formant frequency and amplitude differences between the phonated and whispered productions. In general, the results showed a trend for whispered vowel formants to be higher in frequency than phonated vowel formants, but that trend was only strongly evident for F1.

Two experiments were designed to study whispered and phonated vowel perception. In each experiment, the whispered and phonated test vowel samples were produced by the same subjects. In experiment 1, vowel samples produced by adult female subjects were examined. In experiment 2, vowel samples produced by adult male subjects were examined. In both experiments, whispered and phonated isolated vowels were identified correctly by individual judges in a majority of instances. Phonated vowel samples, generally, were identified correctly more often than whispered vowel samples. The vowels /i, æ, u/ were identified best among phonated vowels; the vowel /i/ was identified best among whispered vowels.

The effects of vocal pitch on the perceived roughess and the acoustic spectral noise levels of two test vowels were investigated. Ten normal-speaking young adult subjects (5 male and 5 female) each produced at one intensity the high vowel /u/ and the low vowel /a/ at four test pitches. The pitches ranged, for each subject, from habitual pitch to a pitch one octave higher. Spectral noise level (SNL) measures and listener ratings of roughness were obtained for each vowel sample, and the fundamental frequency of each sample was measured. It was found that both the mean SNL and the perceived roughness of the test phonations diminished significantly (P< 0·05) when vocal pitch was raised by an octave. This finding held for the two sexes (considered separately) and for both test vowels. When the data were compared across sexes, it was found for each test vowel that the roughness ratings and the SNL means were more closely related to the relative pitch (re subjects’ habitual pitch) at which the test phonations were produced than to the absolute fundamental frequency of phonation.