Australian Acoustical Society ABN 28 000 712 658 A.C.N. 000 712 658

Vol 30 No 2

CONTENTS

August 2002

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ARTICLES

Sound Level Meter Standards for the 21^st Century
B.H. Meldrum
Full Paper

Valuing Noise Impacts Using Hedonic Pricing and Stated Preference Methods: What does the Evidence Tell us?
M. Morrison
Full Paper

The Virtual Boehm Flute - A Web Service that Predicts Multiphonics, Microtones and Alternative Fingerings
A. Botros, J. Smith and J. Wolfe
Full Paper

Acoustic Shock
H. Dillon and M. Fisher
Full Paper

Scattering in the Ocean
L.H. Hamilton (ed.), S. Anstee, P.B. Chapple, M.V. Hall and PJ. Mulhearn
Full Paper

Book Reviews
Meeting Reports
Future Meetings
News Items
New Products
Letters
Obituary
Retirement
FASTS
Standards Australia
New Members
Diary
Acoustics Australia Information
Australian Acoustical Society Information
Advertisers Index

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SOUND LEVEL METER STANDARDS FOR THE 21^st CENTURY

B. H. Meldrum
CSIRO National Measurement Laboratory
Bradfield Road, LINDFIELD NSW 2070

Vol. 30, No. 2 pp 49-54 (2002)
ABSTRACT: A new Sound Level Meter standard IEC61672-1:2002 has just been published. The IEC working group 4 (Sound Level Meters) of the IEC Technical Committee 29 (Electroacoustics) has been engaged for some years in the task of writing this new standard that will replace, update and combine the sound level meter standards IEC60651-1979 and IEC60804-1985. It is reasonable to expect that in due course this new standard will become accepted as an Australian standard and will replace AS1259-1990 parts 1 & 2 which have their technical basis in the older IEC standards of the 80s. As most new Sound Level Meters now coming onto the market have anticipated the new standard it is timely to investigate the differences.

VALUING NOISE IMPACTS USING HEDONIC PRICING AND STATED PREFERENCE METHODS: WHAT DOES THE EVIDENCE TELL US?

Mark Morrison
Faculty of Commerce
Charles Sturt University
< Bathurst

Vol. 30, No. 2 pp 55-60 (2002)
ABSTRACT: Estimates are presented from both Australia and overseas of the value of traffic noise reductions. These estimates were sourced from both hedonic price and stated preference applications. A similar range of estimates was found using both techniques. However, the number of studies available is relatively limited given the importance of noise impacts within the economy, and there is substantial variability in the estimates generated using both techniques. The variability appears to be primarily an artefact of methodological differences rather than differences in cultural perspectives regarding the cost of noise.

THE VIRTUAL BOEHM FLUTE - A WEB SERVICE THAT PREDICTS MULTIPHONICS, MICROTONES AND ALTERNATIVE FINGERINGS

Andrew Botros, John Smith and Joe Wolfe
School of Physics
University of New South Wales, Sydney 2052

Vol. 30, No. 2 pp 61-66 (2002)
ABSTRACT: We report a web service for flute players,'The Virtual Boehm Flute', that provides alternative fingerings which may be easier to play, less awkward to finger and/or more in tune for different circumstances. It also provides possible fingerings for multiphonics (chords). It uses an expert system that predicts the playability of notes from features in the input impedance spectra, based on the playability of 957 impedance minima as determined by an expert flutist. Used in conjunction with a theoretical model, developed from detailed experimental measurements, it can predict the acoustic impedance spectrum for 39,744 different acoustic configurations of the flute. The resulting database provides, via a musician-friendly interface, the predicted possible notes and multiphonics for any selected fingering, and all the possible fingerings predicted to play a desired note or multiphonic. The service is at http://www.phys.unsw.edu.au/music/flute

ACOUSTIC SHOCK

Harvey Dillon and Michael Fisher
National Acoustic Laboratories
Chatswood, NSW

Vol. 30, No. 2 pp 67-70 (2002)
ABSTRACT: Acoustic shock can be a problem to people, such as call-centre operators, who use headsets to make or receive a large number of telephone calls. A device is described that significantly reduces the likelihood of receiving an acoustic shock.

SCATTERING IN THE OCEAN

L.J. Hamilton (editor), S. Anstee, P.B. Chapple, M.V. Hall and P.J. Mulhearn
Maritime Operations Division,
Defence Science & Technology Organisation (DSTO),
P,O, BoH 44, Pyrmont, NSW 2009, Australia

Vol. 30, No. 2 pp 71-77 (2002)
ABSTRACT: Acoustic scattering in the ocean can arise naturally from interactions of sound with suspended particles, volume inhomogeneities, bubbles, the moving random sea surface, the seabed, and organisms, either in resonant or nonresonant processes. Measurements of backscatter stimulated via these processes by active sonar are becoming increasingly useful as remote sensing tools in highly diverse applications. These include assessments of fish stocks and fish migration, seabed and habitat characterization, inferences of turbidity, measurements of waves and currents, and detection of objects. Some of these applications are broadly described, together with the physical scattering mechanisms involved.

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