On the Perception of Spectral Modulations

Abstract

Auditory stimuli are often considered in terms of a spectral shape, an excitation pattern or related concepts. For the perception of complex stimuli, especially if it concerns differences in spectral sharpness, it may be convenient to describe a spectral shape in terms of sinusoidal spectral modulations. For a linear frequency scale, this is closely related to the autocorrelation of a stimulus. In view of the properties of the ear, in this paper a log-frequency scale has been used to define the spectral modulations. Spectral shapes (on a log-frequency scale) are thus described in terms of ripple spectra. According to this approach two experiments are described. The first experiment is concerned with the relation between changes in spectral sharpness of vowel sounds and the resulting perceptual changes. The second experiment deals with the detection thresholds of spectral modulations.