Event, Meeting > Visible Sound [London]
Title: Visible Sound [London]
Location: Royal College of Pathologists, 2 Carlton House Terrace, London, SW1Y 5AF
Description: Lecture by Ian Butterworth, National Physical Laboratory (NPL)
Start Time: 18:30 for 19:00
Date: Tuesday 8th May 2012
Abstract:
Acoustic designers have increasingly accurate and rapid predictive tools at their disposal, enabling progressively impressive and high-fidelity acoustic products. However, the acoustic validation of such techniques still relies upon the use of a physical microphone to be scanned through the sound field through laborious manual adjustments, or requiring complex automated positioning hardware. The challenges in this approach usually result in limited spatial sampling and thus limited validation.
Ian Butterworth will be presenting recent work from the NPL that has enabled the rapid, remote and unperturbing measurement of a sound field using laser based techniques. The methods he has developed allow you to see the propagating waves, much like you would see a surface wave move in a ripple tank.
Exploiting the acousto-optic effect through the use of high sensitivity Laser Scanning Vibrometers, and a novel experimental setup, the new Rapid Acousto-Optic Scanning (RAOS) technique allows a sound field to be autonomously scanned, providing time-gated spatially distributed data that gives a picture of the propagating acoustic field in the time domain. Furthermore,time-averaging can also be employed to show.
The complexities of scanning a 3-dimensional field are discussed with comparison to computer simulations, and studies of various acoustic sources and reflective artefacts, such as QRD diffusers, are shown.
NPL’s Acoustics department undertakes leading-edge research to develop new and improved measurement methods, and holds the UK primary standard for various acoustic measurements, covering Sound-in-Air, Ultrasonics, and Underwater Acoustics.
