Modelling suppression and comodulation masking release using the dual-resonance nonlinear filter.

Martin Gottschalk,Jesko L Verhey

doi:10.1121/10.0009130

Abstract

Although comodulation masking release (CMR) is commonly associated with across-channel processes, it was often argued that part of the effect may be explained by processing within an auditory filter. One peripheral mechanism for such within-channel process is cochlear suppression. Using the dual-resonance nonlinear filter model with different sets of model parameters, the present study shows that the simulated CMR is associated with the simulated two-tone suppression. A modification of the model parameters results in a more accurate prediction of suppression and thus, is also more accurate in predicting the contribution of suppression to CMR.

Highlights

Comodulation masking release (CMR) describes the effect that masked thresholds depend on the correlation of the masker envelope across frequency (Hall et al, 1984)
Using the dual-resonance nonlinear filter model with different sets of model parameters, the present study shows that the simulated comodulation masking release (CMR) is associated with the simulated two-tone suppression
A masking release due to comodulation occurs over spectral distances considerably larger than the width of auditory filters, for which reason the classical interpretation is that CMR depends on acrossfrequency processing (e.g., Hall et al, 1984)

Summary

Introduction

Comodulation masking release (CMR) describes the effect that masked thresholds depend on the correlation of the masker envelope across frequency (Hall et al, 1984). It has been associated with auditory grouping effects and presumably contributes to the ability to recognize speech in noisy environments (e.g., Ihlefeld et al, 2012). In CMR experiments, thresholds are commonly measured for a sinusoidal signal embedded in a masker with on-frequency and off-frequency components If these masker components share the same envelope, thresholds are often lower than in a masking condition with uncorrelated envelopes in different frequency regions. The present study investigated the relative contribution of suppression (as a peripheral within-channel process) to CMR

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