William A. Yost
Parmly Hearing Inst., Loyola Univ. Chicago, 6525 N. Sheridan Rd., Chicago, IL 60626
Two sets of experiments were conducted involving spectra with sinusoidal ripples of amplitude versus frequency. For one set of stimuli the sinusoidal spectral ripple was on a linear frequency scale while for the other set the ripple was on a log frequency scale. For both sets of stimuli ripple frequency and ripple phase were varied. In experiment I, listeners were asked to determine if a change in ripple stimuli was a ripple frequency change or a ripple phase change. They were also asked to differentiate between log and linear ripples. Except for a few conditions, listeners were unable to differentiate between linear and log ripples and between spatial frequency and spatial phase changes. In experiment II, listeners were asked to discriminate between ripple spectra and flat spectra. The ripple spectral depth required for discrimination was approximately the same for both log and linear ripples. The results will be discussed in terms of suggestions that the auditory system performs a type of spatial frequency analysis similar to that performed by the visual system. [Work supported by NIDCD and AFOSR.]