An anechoic chamber is a room in which the walls, floor and ceiling are lined with sound absorbing material, usually foam or glass-fibre wedges.
The lining prevents the reflection of sound from the room boundaries so that 'free-field' conditions exist. The room sounds very 'dead'. Sound measurements are not influenced by the room surfaces, and an anechoic room is an ideal environment for many standard tests such as the measurement of the sound power of a machine, or measurements of microphone and loudspeaker frequency responses.
The Large Anechoic Room at ISVR is one of the largest in the country. It was extensively refurbished in 2022 when new polyurethane wedges, flooring and lighting were installed.
Built as a box within a box, the room is acoustically isolated from the rest of the building and adjacent chambers by an air gap all around. The reinforced concrete walls are 305 mm thick.
There are over 3,200 non-flammable polyurethane foam wedges, extending 1.2 m from the walls, floor and ceiling. Free-field conditions exist at frequencies above 70 Hz.
Without wedges the bare chamber is 9.15 m x 9.15 m x 7.32 m, volume 611 cubic metres. The usable space between the wedges is 6.70 m × 6.70 m (width × depth), and the height from the floor to the ceiling wedge tips is 4.86 m, giving a usable volume of 218 cubic metres.
Outreach visits
To arrange a visit to the anechoic chamber at ISVR contact the Outreach team.
Commercial use
The ISVR test chambers are operated by ISVR Consulting and are well used not only for University research projects, but also for commercial testing and consultancy. For commercial use, contact ISVR Consulting.
The ISVR Consulting website includes further details of the Test chambers and the Laboratory services available.
ISVR Consulting has produced a brief guide to the ISVR Rayleigh Laboratory test facilities. It gives a description of these facilities, including the Large Anechoic Chamber, with photographs showing access routes and dimensions. The guide is intended to assist clients wishing to test large pieces of equipment. You can download and print the latest version here.