ASA 124th Meeting New Orleans 1992 October

1pPP2. Auditory profile analysis of harmonic complexes.

Jan Zera

David M. Green

Psychoacoust. Lab., Psychol. Dept., Univ. of Florida, Gainesville, FL 32611

Spectral shape discrimination of a variety of harmonic complexes was investigated. The signal was an increment in a single component of an otherwise equal-amplitude complex. The focus in these experiments was to determine how the frequency of the signal, the number of components in the complex, and the phases of the components influenced signal detectability. The fundamental frequency was 100, 200, or 400 Hz in spectra ranging up to 6000 Hz. Thresholds increased by almost 30 dB at the highest signal frequencies. These results are understandable because more components fall within the same critical band at the higher frequencies. Thus, the signal caused a lesser change in the output level of a single critical band as more and more nonsignal components were added to the channel. A simple transformation of data were applied to remove the effects of the nonsignal components. The corrected thresholds have a bowl-like shape similar in appearance to that seen in previous studies of spectral shape discrimination where the components of the complex were spaced in frequency at equal logarithmic intervals. [Research supported by AFOSR and the Hays--Fullbright Foundation.]