Numerical Simulation of Air Flow through Glottis during Very Weak Whisper Sound Production

Makoto OTANI; Tatsuya HIRAHARA

doi:10.1587/transfun.E94.A.1779

Numerical Simulation of Air Flow through Glottis during Very Weak Whisper Sound Production

Makoto OTANI, Tatsuya HIRAHARA

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A non-audible murmur (NAM), a very weak whisper sound produced without vocal fold vibration, has been researched in the development of a silent-speech communication tool for functional speech disorders as well as human-to-human/machine interfaces with inaudible voice input. The NAM can be detected using a specially designed microphone, called a NAM microphone, attached to the neck. However, the detected NAM signal has a low signal-to-noise ratio and severely suppressed high-frequency component. To improve NAM clarity, the mechanism of a NAM production must be clarified. In this work, an air flow through a glottis in the vocal tract was numerically simulated using computational fluid dynamics and vocal tract shape models that are obtained by a magnetic resonance imaging (MRI) scan for whispered voice production with various strengths, i.e. strong, weak, and very weak. For a very weak whispering during the MRI scan, subjects were trained, just before the scanning, to produce the very weak whispered voice, or the NAM. The numerical results show that a weak vorticity flow occurs in the supraglottal region even during a very weak whisper production; such vorticity flow provide aeroacoustic sources for a very weak whispering, i.e. NAM, as in an ordinary whispering.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E94-A No.9 pp.1779-1785

Publication Date: 2011/09/01

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Online ISSN: 1745-1337

DOI: 10.1587/transfun.E94.A.1779

Type of Manuscript: PAPER

Category: Speech and Hearing

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Makoto OTANI, Tatsuya HIRAHARA, "Numerical Simulation of Air Flow through Glottis during Very Weak Whisper Sound Production" in IEICE TRANSACTIONS on Fundamentals, vol. E94-A, no. 9, pp. 1779-1785, September 2011, doi: 10.1587/transfun.E94.A.1779.
Abstract: A non-audible murmur (NAM), a very weak whisper sound produced without vocal fold vibration, has been researched in the development of a silent-speech communication tool for functional speech disorders as well as human-to-human/machine interfaces with inaudible voice input. The NAM can be detected using a specially designed microphone, called a NAM microphone, attached to the neck. However, the detected NAM signal has a low signal-to-noise ratio and severely suppressed high-frequency component. To improve NAM clarity, the mechanism of a NAM production must be clarified. In this work, an air flow through a glottis in the vocal tract was numerically simulated using computational fluid dynamics and vocal tract shape models that are obtained by a magnetic resonance imaging (MRI) scan for whispered voice production with various strengths, i.e. strong, weak, and very weak. For a very weak whispering during the MRI scan, subjects were trained, just before the scanning, to produce the very weak whispered voice, or the NAM. The numerical results show that a weak vorticity flow occurs in the supraglottal region even during a very weak whisper production; such vorticity flow provide aeroacoustic sources for a very weak whispering, i.e. NAM, as in an ordinary whispering.
URL: https://globals.ieice.org/en_transactions/fundamentals/10.1587/transfun.E94.A.1779/_p

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@ARTICLE{e94-a_9_1779,
author={Makoto OTANI, Tatsuya HIRAHARA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Numerical Simulation of Air Flow through Glottis during Very Weak Whisper Sound Production},
year={2011},
volume={E94-A},
number={9},
pages={1779-1785},
abstract={A non-audible murmur (NAM), a very weak whisper sound produced without vocal fold vibration, has been researched in the development of a silent-speech communication tool for functional speech disorders as well as human-to-human/machine interfaces with inaudible voice input. The NAM can be detected using a specially designed microphone, called a NAM microphone, attached to the neck. However, the detected NAM signal has a low signal-to-noise ratio and severely suppressed high-frequency component. To improve NAM clarity, the mechanism of a NAM production must be clarified. In this work, an air flow through a glottis in the vocal tract was numerically simulated using computational fluid dynamics and vocal tract shape models that are obtained by a magnetic resonance imaging (MRI) scan for whispered voice production with various strengths, i.e. strong, weak, and very weak. For a very weak whispering during the MRI scan, subjects were trained, just before the scanning, to produce the very weak whispered voice, or the NAM. The numerical results show that a weak vorticity flow occurs in the supraglottal region even during a very weak whisper production; such vorticity flow provide aeroacoustic sources for a very weak whispering, i.e. NAM, as in an ordinary whispering.},
keywords={},
doi={10.1587/transfun.E94.A.1779},
ISSN={1745-1337},
month={September},}

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TY - JOUR
TI - Numerical Simulation of Air Flow through Glottis during Very Weak Whisper Sound Production
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1779
EP - 1785
AU - Makoto OTANI
AU - Tatsuya HIRAHARA
PY - 2011
DO - 10.1587/transfun.E94.A.1779
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E94-A
IS - 9
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - September 2011
AB - A non-audible murmur (NAM), a very weak whisper sound produced without vocal fold vibration, has been researched in the development of a silent-speech communication tool for functional speech disorders as well as human-to-human/machine interfaces with inaudible voice input. The NAM can be detected using a specially designed microphone, called a NAM microphone, attached to the neck. However, the detected NAM signal has a low signal-to-noise ratio and severely suppressed high-frequency component. To improve NAM clarity, the mechanism of a NAM production must be clarified. In this work, an air flow through a glottis in the vocal tract was numerically simulated using computational fluid dynamics and vocal tract shape models that are obtained by a magnetic resonance imaging (MRI) scan for whispered voice production with various strengths, i.e. strong, weak, and very weak. For a very weak whispering during the MRI scan, subjects were trained, just before the scanning, to produce the very weak whispered voice, or the NAM. The numerical results show that a weak vorticity flow occurs in the supraglottal region even during a very weak whisper production; such vorticity flow provide aeroacoustic sources for a very weak whispering, i.e. NAM, as in an ordinary whispering.
ER -