ASA 127th Meeting M.I.T. 1994 June 6-10

5aPP9. Discrimination of multichannel-compressed stop consonants.

E. William Yund

Thomas R. Crain

VA Med. Ctr., 150 Muir Rd., Martinez, CA 94553

The effect of full-range multichannel compression (MCC) on stop consonant discrimination was studied. For normal-hearing subjects MCC was fit to three hypothetical flat losses, with thresholds ranging from 70 to 90 dB SPL, and one hypothetical sloped loss, with thresholds normal at 500 Hz and 90 dB SPL at 4 kHz. Hearing-impaired subjects were tested with the flat MCC as well as MCC fit to the subject's hearing loss. The MCC had compression ratios from 1.75 to 7.00, numbers of channels from 2 to 31, and Robinson--Huntington compression [C. E. Robinson and D. A. Huntington, J. Acoust. Soc. Am. 54, 314 (1973)] with 10-ms time windows. Unprocessed stimuli and frequency-equalized linear amplification were control conditions. Deleterious effects of MCC on discrimination of voice onset time (VOT) were minimal. Normal-hearing subjects had difficulty with stop-consonant place discrimination in the most severe compression conditions. Hearing-impaired subjects needed either fitted MCC or frequency-equalized linear amplification to perform consistent place discriminations on these synthetic vowel--consonant--vowel (VCV) syllables. Complete results and their implications for the application of MCC in hearing aids will be discussed. [Work supported by Department of Veterans Affairs.]