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Aerodynamic and Acoustic Effects of Abrupt Frequency Changes in Excised Larynges
Journal article   Peer reviewed

Aerodynamic and Acoustic Effects of Abrupt Frequency Changes in Excised Larynges

Eileen M Finnegan, Fariborz Alipour and Ronald C Scherer
Journal of speech, language, and hearing research, Vol.52(2), pp.465-481
04/2009
DOI: 10.1044/1092-4388(2008/07-0212)
PMCID: PMC2665729
PMID: 18695011
url
https://www.ncbi.nlm.nih.gov/pmc/articles/2665729View
Open Access

Abstract

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. 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. Abrupt changes in fundamental frequency (F(0)) 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 F(0) changes also occurred for gradual adduction changes, with the chest register corresponding to greater adduction, falsetto to less adduction.
canine larynx chest and falsetto register shift pressure-flow sweep glottal waveform

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