2aPP4. Discrimination of logarithmically and harmonically spaced static and dynamic spectral profiles with and without roving level.

Session: Tuesday Morning, December 3


Author: Ward R. Drennan
Location: Dept. of Speech and Hear. Sci., Indiana Univ., Bloomington, IN 47405
Author: Charles S. Watson
Location: Dept. of Speech and Hear. Sci., Indiana Univ., Bloomington, IN 47405


Listeners' abilities to discriminate profile stimuli were measured using 11-component profiles with component frequencies from 200 to 2200 Hz. The effects of logarithmic versus harmonic spacing of the components and static versus dynamic temporal contours were examined, with and without roving level (20-dB range). Dynamic profiles had a linear frequency glide with a beginning-to-end frequency ratio of 1.28 Hz. The middle component was always the target. Four listeners in the final experiment were the only ones in an initial group of 22 with thresholds below -10 dB (target re: context). The results showed a strong interaction between component spacing and temporal contour. The dynamic changes hinder performance when the spacing is logarithmic and enhance performance when spacing is harmonic. The results are consistent with and without rove. Drennan and Watson [J. Acoust Soc. Am. 99, 2565(A) (1996)] obtained similar results with less stringently selected listeners tested in a no-rove condition. Stimulus properties that might explain this interaction are considered in terms of recent models of complex auditory pattern processing. [Work supported by AFOSR.]

ASA 132nd meeting - Hawaii, December 1996