Dynamic, Compressive Gammachirp Auditory Filterbank for Perceptual Signal Processing

Abstract

A gammachirp auditory filter was developed 1) to extend the domain of the gammatone auditory filter, 2) to simulate the changes in filter shape that occur with changes in stimulus level, 3) to explain a large body of simultaneous masking data, 4) to explain the compressive characteristics of the auditory filter system, and 5) to facilitate the development of a nonlinear, analysis/synthesis framework. What remains is to specify the dynamics of how the stimulus level controls the filter parameters. In this paper, we use psychophysical data involving compression to derive the details of the level control circuit for the dynamic version of the cGC (dcGC) filter and filterbank. The dcGC filterbank enhances spectral contrasts and reduces the dynamic range. This property with the analysis/synthesis framework should be useful in various forms of perceptual signal processing.