2006 Volume 27 Issue 1 Pages 1-11
In this paper, the masked threshold of a sinusoidal signal in the presence of a notched-noise masker was measured experimentally for five normal-hearing subjects. The frequencies of sinusoidal signals used in the measurement were 125, 250, 500, 1,000, 2,000, 4,000, and 6,000 Hz. The conditions and procedure in our measurement were the same as those used by Glasberg and Moore (2000), with additional measurements at 125 and 6,000 Hz. Uniformly excited noise (UEN) was not used in our measurements. The measured data was used to estimate the parameters of a double roex auditory filter as presented in Glasberg and Moore (2000). Basically, this filter is the sum of a tip filter and a tail filter, with its gain controlled by a schematic family of input-output functions. The PolyFit procedure was used to fit the filter to the measured data. An individual auditory filter was fitted at each of the signal frequencies in our measurements. The results showed that auditory filter shape varied with level. The gain of the filters centered at frequencies between 125 Hz and 1,000 Hz, increased as the center frequency increased. Above 1,000 Hz, the gain of the filters remained at a constant value. These results are consistent with the results in Baker et al. (1998) and Glasberg and Moore (2000).
