Effect of Compression Ratio on Speech Recognition and Speech-Quality Ratings With Wide Dynamic Range Compression Amplification This project examined the effect of varying compression ratio on speech recognition and quality. Both listeners with mild-to-moderate sensorineural hearing loss and a control group of listeners with normal hearing participated. Test materials were sentences from the Connected Speech Test (R. M. Cox, G. C. Alexander, & C. Gilmore, 1987) ... Research Article
Research Article  |   April 01, 2000
Effect of Compression Ratio on Speech Recognition and Speech-Quality Ratings With Wide Dynamic Range Compression Amplification
 
Author Affiliations & Notes
  • Kumiko T. Boike
    Department of Speech and Hearing Sciences University of Washington Seattle, WA
  • Pamela E. Souza
    Department of Speech and Hearing Sciences University of Washington Seattle, WA
Article Information
Hearing & Speech Perception / Hearing Disorders / Hearing / Research Articles
Research Article   |   April 01, 2000
Effect of Compression Ratio on Speech Recognition and Speech-Quality Ratings With Wide Dynamic Range Compression Amplification
Journal of Speech, Language, and Hearing Research, April 2000, Vol. 43, 456-468. doi:10.1044/jslhr.4302.456
History: Received March 22, 1999 , Accepted October 25, 1999
 
Journal of Speech, Language, and Hearing Research, April 2000, Vol. 43, 456-468. doi:10.1044/jslhr.4302.456
History: Received March 22, 1999; Accepted October 25, 1999

This project examined the effect of varying compression ratio on speech recognition and quality. Both listeners with mild-to-moderate sensorineural hearing loss and a control group of listeners with normal hearing participated. Test materials were sentences from the Connected Speech Test (R. M. Cox, G. C. Alexander, & C. Gilmore, 1987) which were digitally processed with linear amplification and wide dynamic range compression amplification with 3 compression ratios. Speech-recognition scores were obtained with sentences in quiet and in noise at a 10-dB signal-to-noise ratio for each amplification condition. Additionally, the participants rated each amplification condition in terms of clarity, pleasantness, ease of understanding, and overall impression. Results indicated that, for speech in quiet, compression ratio had no effect on speech-recognition scores; however, speech-quality ratings decreased as compression ratio increased. For speech in noise, both speech-recognition scores and ratings decreased with increasing compression ratio for the listeners with hearing loss. These results suggest that selection of compression ratio on the basis of speech-quality judgments does not compromise speech recognition.

Acknowledgments
This work was supported in part by a personnel training grant (T32 DC00033) from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health, and the University of Washington, Department of Speech and Hearing Sciences, to the first author and by a Deafness Research Foundation grant to the second author. The authors gratefully acknowledge the assistance of Steve Armstrong and Gennum Corporation in providing the compression simulation software. The authors thank Lynne Werner and Lori Leibold for their helpful comments on a previous version of this manuscript, and Laurel Christensen, Larry Humes, Chris Turner, and an anonymous reviewer for their comments.
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