Economic Design and Construction of Anechoic Chambers

For the past 16 years, the design of anechoic chambers has been the subject of a good deal of acoustic research. Prior research has yielded a design employing a large number of light‐density wedges (2.S lb/ft3) which had to be supported a fixed distance from the chamber wall. The design considerations which formed the nucleus of a research program by the Industrial Acoustics Company, Inc., were the following: (1) The wedge had to be made of a rigid material. (2) The over‐all length of any anechoic wedge must be maintained as short as physically possible. (3) The wall area covered by a single wedge should be made as large as possible. The first series of investigations made was to determine whether or not the conventional air space could be eliminated. Two figures showing test results of two particular experiments indicate that, if the wedge sizes were maintained constant, there is no advantage in having the air space behind them. It was also observed that the low‐frequency absorption could be matched to t...