Aerodynamic and Acoustic Effects of Abrupt Frequency Changes in Excised Larynges Purpose To determine the aerodynamic and acoustic effects due to a sudden change from chest to falsetto register or vice versa. It was hypothesized that the continuous change in subglottal pressure and flow rate alone (pressure-flow sweep [PFS]) can trigger a mode change in the canine larynx. Method ... Research Article
Research Article  |   April 01, 2009
Aerodynamic and Acoustic Effects of Abrupt Frequency Changes in Excised Larynges
 
Author Affiliations & Notes
  • Fariborz Alipour
    The University of Iowa, Iowa City
  • Eileen M. Finnegan
    The University of Iowa, Iowa City
  • Ronald C. Scherer
    The University of Iowa
    Bowling Green State University, Bowling Green, OH
  • Contact author: Fariborz Alipour, 334E WJSHC, The University of Iowa, Iowa City, IA 52242-1012. E-mail: alipour@iowa.uiowa.edu.
Article Information
Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 01, 2009
Aerodynamic and Acoustic Effects of Abrupt Frequency Changes in Excised Larynges
Journal of Speech, Language, and Hearing Research, April 2009, Vol. 52, 465-481. doi:10.1044/1092-4388(2008/07-0212)
History: Received September 7, 2007 , Revised November 26, 2007 , Accepted June 9, 2008
 
Journal of Speech, Language, and Hearing Research, April 2009, Vol. 52, 465-481. doi:10.1044/1092-4388(2008/07-0212)
History: Received September 7, 2007; Revised November 26, 2007; Accepted June 9, 2008
Web of Science® Times Cited: 5

Purpose To determine the aerodynamic and acoustic effects due to a sudden change from chest to falsetto register or vice versa. It was hypothesized that the continuous change in subglottal pressure and flow rate alone (pressure-flow sweep [PFS]) can trigger a mode change in the canine larynx.

Method Ten canine larynges were each mounted over a tapered tube that supplied pressurized, heated, and humidified air. Glottographic signals were recorded during each PFS experiment, during which airflow was increased in a gradual manner for a period of 20–30 s.

Results Abrupt changes in fundamental frequency (F0) and mode of vibration occurred during the PFS in the passive larynx without any change in adduction or elongation. The lower frequency mode of oscillation of the vocal folds, perceptually identified as the chest register, had relatively large amplitude oscillation, significant vocal fold contact, a rich spectral content, and a relatively loud audio signal. The higher frequency mode of oscillation, perceptually identified as falsetto, had little or no vocal fold contact and a dominant first partial. Relatively abrupt F0 changes also occurred for gradual adduction changes, with the chest register corresponding to greater adduction, falsetto to less adduction.

Acknowledgments
This work was supported by National Institute on Deafness and Other Communication Disorders Grant DC03566. We would like to thank Sanyukta Jaiswal and Jaclyn Curiel for their assistance in data collection and David Berry for his helpful comments.
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