Vol 30 No 2 | CONTENTS |
August 2002 |
Sound Level Meter Standards for the 21st Century
B.H. Meldrum
Valuing Noise Impacts Using Hedonic Pricing and Stated Preference Methods: What does the Evidence Tell us?
M. Morrison
The Virtual Boehm Flute - A Web Service that Predicts Multiphonics, Microtones and Alternative Fingerings
A. Botros, J. Smith and J. Wolfe
Acoustic Shock
H. Dillon and M. Fisher
Scattering in the Ocean
L.H. Hamilton (ed.), S. Anstee, P.B. Chapple, M.V. Hall and PJ. Mulhearn
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
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.
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.
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
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.
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.