Characteristics of the glottal turbulent noise source

This investigation utilized a reflectionless tube technique to obtain direct estimates of turbulent noise produced at the glottis during whispered vowels. In the past, the glottal turbulent noise source has been described theoretically as a series pressure source having a spectrum that is relatively flat for 2 or 3 oct around a center frequency [K.N. Stevens, J. Acoust. Soc Am. 50, 1180-1192 (1971)]. Center frequency is determined primarily by the area of the constriction at which turbulence is produced with the volume velocity of air flowing through the constriction. The present results were shown to substantiate this theoretically based description of the glottal turbulent noise source. In addition, there was no significant difference between the glottal turbulent noise spectra of male and female speakers. The application of these findings to the synthesis of whispered vowels is discussed.