The Design and Evaluation of an Economically Constructed Anechoic Chamber

Abstract This paper reports on a study of the design of an economic anechoic chamber so that a controlled environment would be readily available for acoustic experiments such as 3-D audio playback through a spherical loudspeaker array. It describes measurements performed to evaluate the room's acoustical performance against ISO 3745 and some ITU-R BS.1116-1 recommendations. Two custom omnidirectional sound sources were developed for the mid and high frequency range to perform some of these measurements. The data from these measurements indicate that the room has a noise rating of NR15; the carpeted floor absorbs at least 50% of incident sound energy above 400 Hz, and the room exhibits free-field conditions in all directions tested up to 2 m from the centre of the room between 400 Hz and 20 kHz. Hence, this paper presents a model of how an economic anechoic chamber could be designed for high-resolution spatial audio applications (such as audio reproduction using high order ambisonics), and how such a room's acoustic performance can be assessed.

[1]  R. H. Bolt.  Note on Normal Frequency Statistics for Rectangular Rooms , 1946 .

[2]  Éva Arató Borsi,et al.  New Reference Listening Room for Two-Channel and Multichannel Stereophonic , 1998 .

[3]  M. E. Delany,et al.  The high frequency performance of wedge-lined free field rooms , 1977 .

[4]  R. Walker,et al.  A Controlled-Reflection Listening Room for Multi-Channel Sound , 1998 .

[5]  Jörg M. Buchholz,et al.  Flat-walled multilayered anechoic linings: Optimization and application , 2005 .

[6]  Toshiyuki Mizutani,et al.  A New Type of Listening Room and its Characteristics: A Proposal for a Standard Listening Room , 1982 .

[7]  R. Walker,et al.  Optimum Dimension Ratios for Small Rooms , 1996 .

[8]  Leo L. Beranek,et al.  The Design and Construction of Anechoic Sound Chambers , 1946 .

[9]  K. O. Ballagh.  Calibration of an anechoic room , 1986 .

[10]  Juhani Borenius,et al.  New Aspects on Listening Room Design , 1985 .

[11]  Lauri Savioja,et al.  Design of a Reference Listening Room-A Case Study , 1997 .

[12]  Trevor J. Cox,et al.  Determining Optimum Room Dimensions for Critical Listening Environments: A New Methodology , 2001 .

[13]  Walter Koidan,et al.  Acoustical properties of the National Bureau of Standards anechoic chamber , 1978 .

[14]  John Tran,et al.  Anechoic chamber qualification: traverse method, inverse square law analysis method, and nature of test signal. , 2003, The Journal of the Acoustical Society of America.

[15]  Kenneth A. Cunefare,et al.  A test system for free-field qualification of anechoic chambers , 2003 .