Analysis of modal and creaky voice quality variations
Avanti Satish Shetye, Carol Espy-Wilson · The Journal of the Acoustical Society of America · 2005
Voice quality, as a major vehicle of information about physical, phonological, and social characteristics of the speaker, has a vital semiotic role to play in spoken interaction [Laver (1968), Laver and Trudgill (1979)]. In the past couple of years, our lab developed an Aperiodicity/Periodicity/Pitch (APP) detector that produces a spectro-temporal profile of the periodic and aperiodic regions of the speech waveform [Deshmukh et al. (in press)]. To do so, the speech signal is passed through a 60-channel gamma tone auditory filterbank. The distribution of the dips occurring in the average magnitude difference function (AMDF) computed from each channel envelope is analyzed to determine periodicity and aperiodicity. Presently, the APP detector classifies both turbulent noise and irregular vocal fold vibration (creakiness) as aperiodic. In this work, we are investigating the detailed characteristics of the AMDF waveform when speech is creaky. This information is presently being used to distinguish aperiodicity due to turbulence from aperiodicity due to creakiness. We will present results from the refined APP detector using various male and female utterances from the TIMIT database.