On the auditory discrimination of spectral shape

VIII+142hlm.;24c

Perception of spectral changes in noise bands of varying bandwidth

Thresholds for a change in the spectral slope of noise bands were measured as a function of the bandwidth. A roving intensity level was introduced to prevent subjects from using loudness cues. Results show that subjects are able to discriminate sounds on the basis of the change in spectral shape, which indicates that they can compare relative energy changes in the different critical bands simultaneously (profile analysis). Detection of changes in the spectral slope is dependent on the bandwidth and reaches a minimum value near 3 - 6 semitones (ST). For bandwidths smaller than 1 ST, results can be explained in terms of a model that states that spectral changes are perceived as changes in pitch. For greater bandwidths the auditory system is not able to compare the output of all critical bands together, as in a filter-bank model, but rather focusses on only two or perhaps a few more critical-band regions

Intensity changes in two-tone complexes and model predictions

Thresholds for changes in the amplitudes of two-tone complexes have been measured as a function of frequency separation. Thresholds have been measured both with and without a roving intensity level. Thresholds for changes in the spectral shape of two-tone complexes were generally lower than those for changes in the overall intensity. Thresholds for the former changes are lowest at a frequency separation of one semitone. Thresholds for the latter decrease as a function of frequency separation. Two models have been applied to the data. For narrow-bandwidth signals, the EWAIF model [Feth, Percept. Psychophys. 15, 375–378 (1974)] can partly account for the obtained data. For (partially) resolved signals, the two-channel model [Durlach et al., J. Acoust. Soc. Am. 80, 63–72 (1986)] can account for the data. The obtained values of the model parameters show that the auditory system does not process the changes optimally, in the sense that amplitude changes in one component contribute more in the detection process than those in the other component

On the perception of spectral changes in noise bands

No abstrac

On the perception of spectral changes in noise bands

No abstrac