The ARL/FED anechoic chamber
Abstract
This report documents the design and acoustic characteristics of the Applied Research Laboratory Department anechoic chamber. It is located on the above-console deck of the Garfield Thomas Water Tunnel situated so as to allow its use in conjunction with the Axial Flow Research Fan (AFRF). The internal free dimensions of the chamber are 2.74 x 3.05 x 1.98 meters (9 x 10 x 6.5 ft.). The sound absorbing walls are composed of polyurethane foam acoustic wedges, air voids, embossed acoustic foam wall lining, plywood and wood frame members. Air intake ducts, baffled and lined with a lead-foam sheet, provide an adequate air volume for the AFRF. Based on measurements of transmission loss and inverse square law, the chamber is considered anechoic for frequencies above 230 Hz and semi-anechoic for lower frequencies.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- August 1981
- Bibcode:
- 1981STIN...8216376M
- Keywords:
-
- Acoustic Measurement;
- Acoustic Properties;
- Anechoic Chambers;
- Acoustics;
- Construction;
- Structural Engineering;
- Instrumentation and Photography