Theoretical Analysis of Maximum Flow Declination Rate Versus Maximum Area Declination Rate in Phonation Purpose Maximum flow declination rate (MFDR) in the glottis is known to correlate strongly with vocal intensity in voicing. This declination, or negative slope on the glottal airflow waveform, is in part attributable to the maximum area declination rate (MADR) and in part to the overall inertia of the air ... Research Article
Research Article  |   April 01, 2006
Theoretical Analysis of Maximum Flow Declination Rate Versus Maximum Area Declination Rate in Phonation
 
Author Affiliations & Notes
  • Ingo R. Titze
    The University of Iowa, Iowa City, IA, and National Center for Voice and Speech, The Denver Center for the Performing Arts, Denver, CO
  • Contact author: Ingo R. Titze, The Denver Center for the Performance Arts, National Center for Voice and Speech, 1101 13th Street, Denver, CO 80204-5319. Email: ititze@dcpa.org
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 01, 2006
Theoretical Analysis of Maximum Flow Declination Rate Versus Maximum Area Declination Rate in Phonation
Journal of Speech, Language, and Hearing Research, April 2006, Vol. 49, 439-447. doi:10.1044/1092-4388(2006/034)
History: Received June 8, 2004 , Accepted August 7, 2005
 
Journal of Speech, Language, and Hearing Research, April 2006, Vol. 49, 439-447. doi:10.1044/1092-4388(2006/034)
History: Received June 8, 2004; Accepted August 7, 2005

Purpose Maximum flow declination rate (MFDR) in the glottis is known to correlate strongly with vocal intensity in voicing. This declination, or negative slope on the glottal airflow waveform, is in part attributable to the maximum area declination rate (MADR) and in part to the overall inertia of the air column of the vocal tract (lungs to lips). The purpose of this theoretical study was to show the possible contributions of air inertance and MADR to MFDR.

Method A simplified computational model of the kinematics of vocal fold movement was utilized to compute a glottal area function. The glottal flow was computed interactively with lumped vocal tract parameters in the form of resistance and inertive reactance.

Results It was shown that MADR depends almost entirely on the ratio of vibrational amplitudes of the lower to upper margins of the vocal fold tissue. Adduction, vertical phase difference, and prephonatory convergence of the glottis have a lesser effect on MADR. A relatively simple rule was developed that relates MFDR to a vibrational amplitude ratio and vocal tract inertance.

Conclusion It was concluded that speakers and singers have multiple options for control of intensity, some of which involve more source–filter interaction than others.

Acknowledgment
This research was supported by Grant 5R01-DC04224-06 from the National Institute on Deafness and Other Communication Disorders.
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