Preserving Spectral Contrast in Amplitude Compression for Hearing Aids

Amplitude compression processing is used to reduce the amplitude level variations of speech to fit the reduced dynamic ranges of sensorineural impaired listeners. However this processing results in spectral smearing due in part to reduced peak-to-valley ratios. Presented here are two variations of a compression processing algorithm based on a sinusoidal speech model that preserves the important spectral peaks. Both models operate on a time-varying, frequencydependent basis to adjust to the speech variations and the listenerís hearing profile. Preliminary subject tests indicate benefit from preserving spectral contrast. Enhancing spectral contrast is possible with the algorithm presented here.