Two phase effects in roughness perception.

The respective influences of spectral and temporal aspects of sound in roughness perception are examined by way of phase manipulations. In a first experiment, the phase of the central component of three-component signals is shown to modify perceived roughness, for a given amplitude spectrum, regardless of whether it modifies the waveform envelope. A second experiment shows that the shape of the waveform envelope, for a given amplitude spectrum and a given modulation depth, also influences perceived roughness. We interpret both of these results by considering the envelope of an internal representation that is deduced from the physical signal by taking into account peripheral auditory processing. The results indicate that the modulation depth of such an internal representation is not the only determinant of roughness, but that an effect of temporal asymmetry is also to be taken into account.