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Vol 37 No 1

CONTENTS

April 2009


ARTICLES

A comparison of two techniques that measure vocal tract shape
Catherine I. Watson, C. William Thorpe and Xiao Bo Lu
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Influence of resonance changer parameters on the radiated sound power of a submarine
Sascha Merz, Nicole Kessissoglou and Roger Kinns
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Saxophone Acoustics: Introducing a compendium of impedance and sound spectra
Jer-Ming Chen, John Smith and Joe Wolfe
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TECHNICAL NOTES

Amendment for wind farms environmental noise guidelines
Valeri V. Lenchine
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Using ISO 8253 to calculate the maximum permissible background sound pressure levels for audiometric testing
W. Williams
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Noise and vibration design of the Monash Centre for Electron Microscopy building
Matthew Stead, Simon Moore, Jon Cooper and Andrew Mitchell
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A comparison of two techniques that measure vocal tract shape

Catherine I. Watson1, C. William Thorpe2, Xiao Bo Lu2
1Department of Electrical and Computer Engineering
2Bioengineering Institute, The University of Auckland

Vol. 37, No. 1 pp 7 - 11 (2009)
ABSTRACT: This study compares vocal tract shapes of four vowels for a single speaker estimated via analysis of magnetic resonance images and acoustic reflectometer measurements. The first and second resonances of the vocal tract shapes from the two different methods are compared to the first and second formants obtained from an acoustic analysis of the speech signal. It is demonstrated that speech production is compromised by the mouthpiece used for the acoustic reflectometer, and as such this tool is not useful for studying articulatory phonetics.

Influence of resonance changer parameters on the radiated sound power of a submarine

Sascha Merz, Nicole Kessissoglou and Roger Kinns
School of Mechanical and Manufacturing Engineering,
The University of New SouthWales,
Sydney NSW 2052, Australia

Vol. 37, No. 1 pp 12 - 17 (2009)
ABSTRACT: Sound radiation from a submarine in the low frequency range is mainly due to fluctuating forces at the propeller. The forces arise due to the operation of the propeller in a non-uniform wake and are transmitted to the hull via the shaft and the fluid. The overall sound radiation from the submarine is the combination of sound radiated from the hull and sound radiated from the propeller. A hydraulic vibration attenuation device known as a resonance changer can be implemented in the propeller/shafting system in order to reduce the overall radiated sound power. In this paper, the influence of the virtual stiffness and damping of the resonance changer on the radiated sound power is investigated, where the importance of sound radiation from the propeller and the resulting re-excitation of the hull is of particular interest. Finite and boundary element methods are employed to model the structure and the fluid, respectively.

Saxophone Acoustics: Introducing a compendium of impedance and sound spectra

Jer-Ming Chen, John Smith and Joe Wolfe,
School of Physics,
University of New South Wales,
Sydney 2052 NSW

Vol. 37, No. 1 pp 18 - 23 (2009)
ABSTRACT: We introduce a web-based database that gives details of the acoustics of soprano and tenor saxophones for all standard fingerings and some others. It has impedance spectra measured at the mouthpiece and sound files for each standard fingering. We use these experimental impedance spectra to explain some features of saxophone acoustics, including the linear effects of the bell, mouthpiece, reed, register keys and tone holes. We also contrast measurements of flute, clarinet and saxophone, to give practical examples of the different behaviour of waveguides with open-open cylindrical, closed-open cylindrical and closed-open conical geometries respectively.

 

Newsflash

PROPOSED INTERNATIONAL YEAR OF SOUND 2019

Let's make 2019 the International Year of Sound!

Click here to see draft prospectus. Suggestions for major activities that would be truly international to strengthen the application are welcomed.

 

ACOUSTICS 2017

Perth, Western Australia 19-22 November 2017