Home Journal
E-mail Print
Acoustics Australia Logo (3032 bytes)

Vol 23 No 2

CONTENTS

August 1995


ARTICLES

Low Frequency Absolute Calibration of Accelerometers
N C Clark
PDF Full Paper

Noise and Vibration Data Acquisition using a 16 bit PC Sound Card
I Howard
PDF Full Paper

Orchestral Music: An Assessment of Risk
K Mikl
PDF Full Paper

Simulation of a Ripple Tank
S Zhu and J McKerrow
PDF Full Paper

NOTES

Back on the FASTS Track
K Baldwin and R. Crompton
PDF Full Paper

Wind Generated Tonal Noise? A Practical Solution
R T Benbow
PDF Full Paper

News
New Members
New Products
Book Reviews
Letters
Acoustics Australia Information
Australian Acoustical Society Information
Advertisers Index
Diary


Low Frequency Absolute Calibration of Accelerometers

Norman H. Clark
Division of Applied Physics, CSIRO,
National Measurement Laboratory
PO Box 218, Lindfield, NSW 2070 Australia

Vol. 23, No. 2 pp 39-43 (1995)
ABSTRACT: At the National Measurement Laboratory, Australia, apparatus and techniques have been developed for calibrating vibration-measuring transducers in the low-frequency range, 2Hz - 250Hz. This paper describes the apparatus and the methods used to calibrate the built-in reference accelerometers absolutely in terms of the primary standards of length, time and voltage.

Noise and Vibration Data Acquisition using a 16 bit PC Sound Card

Ian Howard
Mechanical Engineering Department
Curtin University of Technology
Perth, Western Australia

Vol. 23, No. 2 pp 45-49 (1995)
ABSTRACT: Noise and vibration data acquisition cards for the Personal Computer have been available for about 10 years, commencing with 8 bit, then 12 bit and now 16 bit plug in cards. The data acquisition capabilities available range from two up to 64 or more channels, with sampling rate capabilities from a thousand samples per second to well over one million samples per second. The range of plug in cards available on the market is enormous. For a particular application, it is no easy task to determine the cheapest card available to meet the actual requirements. For data acquisition and analysis of rotating machinery noise and vibration, a frequency bandwidth of 10 to 20 kHz per channel is normally required. Unfortunately, the cost of special purpose 12 or 16 bit cards with this bandwidth tends to be at least two thousand dollars. This paper presents a detailed investigation, calibration and analysis of a mass market 16 bit sound card which is now available for under two hundred dollars and which has adequate performance for the analysis of rotating machinery noise and vibration. The data acquisition capabilities under the windows environment are discussed along with channel calibration, amplitude and phase response and the ease of transferring the data to post-processing environments such as MATLAB.

Orchestral Music: An Assessment of Risk

Ken Mikl
Acoustic Services
WorkCover Authority NSW
132 Londonderry Rd
LONDONDERRY NSW 2753

Vol. 23, No. 2 pp 51-55 (1995)
ABSTRACT: Worldwide, a reasonable number of measurements have been made of the type of sound levels to which Orchestral Musicians are exposed. The conclusions are in conflict when compared in isolation because the previous studies have given little data as to true exposure levels over a longer period. The current study traces the sound exposure at various positions within a Classical Orchestra performing for Opera and Ballet in an orchestra pit. It determines Noise Exposure based on type and length of performance, rehearsal etc. on a daily basis for a full season of works. The results, when compared to industrial criteria for noise exposure, are relatively high as many musicians are often being exposed to levels over 90dB(A). The only person in the orchestra without risk is the conductor. The audience is also not at risk of NIHL.

Simulation of a Ripple Tank

Shao-Min Zhu and Phillip John McKerrow
Department of Computer Science,
University of Wollongong,
Wollongong, NSW 2522, Australia

Vol. 23, No. 2 pp 57-63 (1995)
ABSTRACT: Visualisation of the reflection of waves off objects is useful in education, because we cannot see sound waves. Techniques for visualising sound rail into four groups: listening, mechanical analogues, measurement, and computer simulation. This paper describes efforts to develop the computer graphics equivalent of a ripple tank.

Back on the FASTS Track

K Baldwin and R. Crompton

Vol. 23, No. 2 pp 64-65 (1995)

Wind Generated Tonal Noise? A Practical Solution

R T Benbow
Principal Consultant,
Dick Benbow & Associates Pty Limited

Vol. 23, No. 2 pg 66 (1995)

 

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