Multichannel Compression: Effects of Reduced Spectral Contrast on Vowel Identification PurposeTo clarify if large numbers of wide dynamic range compression channels provide advantages for vowel identification and to measure its acoustic effects.MethodsEight vowels produced by 12 talkers in the /hVd/ context were compressed using 1, 2, 4, 8, and 16 channels. Formant contrast indices (mean formant peak minus mean formant ... Article
Article  |   October 2008
Multichannel Compression: Effects of Reduced Spectral Contrast on Vowel Identification
 
Author Affiliations & Notes
  • Stephanie Bor
    University of Washington, Seattle
  • Pamela Souza
    University of Washington, Seattle
  • Richard Wright
    University of Washington, Seattle
  • Contact author: Stephanie Bor, Hearing Aid Laboratory, Department of Speech and Hearing Sciences, University of Washington, 1417 N.E. 42nd Street, Box 354875, Seattle, WA 98105-6246. E-mail: stebor@u.washington.edu.
  • © 2008 American Speech-Language-Hearing Association
Article Information
Hearing Disorders / Speech, Voice & Prosody / Hearing
Article   |   October 2008
Multichannel Compression: Effects of Reduced Spectral Contrast on Vowel Identification
Journal of Speech, Language, and Hearing Research, October 2008, Vol. 51, 1315-1327. doi:10.1044/1092-4388(2008/07-0009)
History: Received January 15, 2007 , Revised August 16, 2007 , Accepted January 5, 2008
 
Journal of Speech, Language, and Hearing Research, October 2008, Vol. 51, 1315-1327. doi:10.1044/1092-4388(2008/07-0009)
History: Received January 15, 2007; Revised August 16, 2007; Accepted January 5, 2008
Web of Science® Times Cited: 22

PurposeTo clarify if large numbers of wide dynamic range compression channels provide advantages for vowel identification and to measure its acoustic effects.

MethodsEight vowels produced by 12 talkers in the /hVd/ context were compressed using 1, 2, 4, 8, and 16 channels. Formant contrast indices (mean formant peak minus mean formant trough; maximum formant peak minus minimum formant trough) were developed to quantify spectral changes. Twenty listeners with mild to moderately severe sensorineural hearing loss identified the compressed vowels in an 8-alternative forced-choice procedure.

ResultsFormant contrast measures revealed significant spectral flattening for 6 of the 8 vowels as channel number increased. A significant decrease in vowel identification performance was also observed as spectral contrast decreased.

ConclusionsIncreasing the number of wide dynamic range compression channels may not be beneficial for all speech signals, and individual vowel identification performance can vary greatly for listeners with similar hearing loss.

Acknowledgments
This study was supported by the Bloedel Hearing Research Center, Training Grant DC00033 from the National Institute on Deafness and Other Communication Disorders, and National Institutes of Health RO1 Grant DC006014. The authors acknowledge Marc Caldwell, Dennis Tang, and Kerry Witherall for their assistance in data collection, processing, and analysis, and Steve Armstrong and Gennum Corporation for providing the compression simulation software. Portions of this work were presented at the 2005 Acoustical Society of America Meeting in Minneapolis, MN; the 2006 Acoustical Society of America Meeting in Honolulu, HI; and the 2006 American Auditory Society Conference in Scottsdale, AZ.
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