Consequences of broad auditory filters for identification of multichannel-compressed vowels

Purpose: In view of previous findings (Bor, Souza, & Wright, 2008) that some listeners are more susceptible to spectral changes from multichannel compression (MCC) than others, this study addressed the extent to which differences in effects of MCC were related to differences in auditory filter width. Method: Listeners were recruited in 3 groups: listeners with flat sensorineural loss, listeners with sloping sensorineural loss, and a control group of listeners with normal hearing. Individual auditory filter measurements were obtained at 500 and 2000 Hz. The filter widths were related to identification of vowels processed with 16-channel MCC and with a control (linear) condition. Results: Listeners with flat loss had broader filters at 500 Hz but not at 2000 Hz compared with listeners with sloping loss. Vowel identification was poorer for MCC compared with linear amplification. Listeners with flat loss made more errors than listeners with sloping loss, and there was a significant relationship between filter width and the effects of MCC. Conclusions: Broadened auditory filters can reduce the ability to process amplitude-compressed vowel spectra. This suggests that individual frequency selectivity is a factor that influences benefit of MCC when a high number of compression channels are used.