James M. Kates

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The speech intelligibility index (SII) (ANSI S3.5-1997) provides a means for estimating speech intelligibility under conditions of additive stationary noise or bandwidth reduction. The SII concept for estimating intelligibility is extended in this paper to include broadband peak-clipping and center-clipping distortion, with the coherence between the input(More)
PURPOSE This study examined how frequency lowering affected sentence intelligibility and quality for adults with postlingually acquired, mild-to-moderate hearing loss. METHOD Listeners included adults aged 60-92 years with sloping sensorineural hearing loss and a control group of similarly aged adults with normal hearing. Sentences were presented in quiet(More)
Noise and distortion reduce speech intelligibility and quality in audio devices such as hearing aids. This study investigates the perception and prediction of sound quality by both normal-hearing and hearing-impaired subjects for conditions of noise and distortion related to those found in hearing aids. Stimuli were sentences subjected to three kinds of(More)
A multichannel dynamic-range compressor system using digital frequency warping is described. A frequency-warped filter is realized by replacing the filter unit delays with all-pass filters. The appropriate design of the frequency warping gives a nonuniform frequency representation very close to the auditory Bark scale. The warped compressor is shown to have(More)
In feedback cancellation in hearing aids, an adaptive filter is used to model the feedback path. The output of the adaptive filter is subtracted from the microphone signal to cancel the acoustic and mechanical feedback picked up by the microphone, thus allowing more gain in the hearing aid. In general, the feedback-cancellation filter adapts on the(More)
OBJECTIVES Hearing aids use complex processing intended to improve speech recognition. Although many listeners benefit from such processing, it can also introduce distortion that offsets or cancels intended benefits for some individuals. The purpose of the present study was to determine the effects of cognitive ability (working memory) on individual(More)
Room reverberation can affect feedback cancellation in hearing aids, with the strength of the effects depending on the acoustical conditions. These effects were studied using a behind the ear (BTE) hearing aid mounted on a dummy head and coupled to the ear canal via an open fitting. The hearing aid impulse response was measured for the dummy head placed at(More)