Formant-frequency differences between isolated whispered and phonated vowel samples produced by adult female subjects.

This study was designed to investigate the formant frequencies of phonated and whispered productions of five test vowels (/i/, /u/, /ae/, /a/). Each test vowel was sustained twice in isolation--once phonated, one whispered--by 20 adult female subjects. The phoneme represented by each recorded production was identified independently by 11 listeners. Only those samples identified by 6 or more of the listeners as the vowel intended were retained for a further (acoustic) analysis. An acoustic spectrum of each retained sample was obtained to permit formant measurements. To provide the clearest formant delineation possible in our lab, the phonated samples were analyzed by broadband spectrography and the whispered samples by very narrow-band spectrography. This report presents the formant frequencies (F1-F3) of the test productions as measured from the acoustic vowel spectra and the formant-frequency 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.