Tone-vs.-Noise Dichotomy in Psychoacoustics Could be Resolved by Careful Consideration of Cochlear Signal Processing

Abstract

Psychoacoustic research suggests that the human auditory system processes noise and tones differently. For example, narrowband noise has a stronger masking effect than a pure tone at the same sound pressure level. Can this be explained by cochlear mechanics, or is the distinction due to central neural processing? In this paper, we review a computational model that simulates wave propagation in the cochlea. The model incorporates recent findings in cochlear electrophysiology and describes wave propagation in both the forward and the backward direction. Simulation shows that the model produces compressive nonlinear responses to tones but quasilinear responses to noise. We may therefore argue that the distinction between tone-and noise-processing is an epiphenomenon of cochlear mechanics. If this is true, we can simplify the computational organization of audio signal-processing front-ends for applications such as hearing aids and auditory prostheses.