AUDITORY FILTER SHAPES AT HIGH-FREQUENCIES

The shape of the auditory filter was estimated at center frequencies of 4, 12, 14, and 16 kHz for normally hearing subjects, using the notched-noise method. A specially designed sound delivery system was used to generate a high-frequency masking noise with a flat spectrum. For all test frequencies, the auditory filter Shapes were estimated at a noise spectrum level (N-0) of 40 dB. The mean equivalent rectangular bandwidths (ERBs) of the auditory filter at 4, 12, and 14 kHz were close to the extrapolated values given by Glasberg and Moore [Hear. Res. 47, 103-108 (1990)]. At 16 kHz, the mean ERB was close to the extrapolated value given by Moore and Glasberg [J. Acoust. Sec. Am. 74, 750-753 (1983)]. At 12 and 14 kHz, the auditory filter shapes were also estimated at a noise spectrum level of 50 dB. The mean ERBs of the auditory filter were wider for the higher spectrum level, consistent with previous results obtained at lower center frequencies. (C) 1995 Acoustical Society of America.