An Oral Pressure Conversion Ratio as a Predictor of Vocal Efficiency

  • Ingo R. Titze
    Address correspondence and reprint requests to Ingo R. Titze, National Center for Voice and Speech, The University of Utah, 136 South Main Street, Suite 320, Salt Lake City, UT 84101-3306.
    National Center for Voice and Speech, The University of Utah, Salt Lake City, Utah

    Department of Communication Sciences and Disorders, The University of Iowa, Iowa City, Iowa
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  • Lynn Maxfield
    National Center for Voice and Speech, The University of Utah, Salt Lake City, Utah
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  • Anil Palaparthi
    National Center for Voice and Speech, The University of Utah, Salt Lake City, Utah
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      Voice production is an inefficient process in terms of energy expended versus acoustic energy produced. A traditional efficiency measure, glottal efficiency, relates acoustic power radiated from the mouth to aerodynamic power produced in the trachea. This efficiency ranges between 0.0001% and 1.0%. It involves lung pressure and hence would appear to be a useful effort measure for a given acoustic output. Difficulty in the combined measurement of lung pressure and tracheal airflow, however, has impeded clinical application of glottal efficiency. This article uses the large data base from Schutte (1980) and a few new measurements to validate a pressure conversion ratio (PCR) as a substitute for glottal efficiency. PCR has the potential for wide application because of low cost and ease of use in clinics and vocal studios.

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