Maa Dah-You and the design of reverberant rooms for determination of sound power

Abstract

Reverberation rooms are useful tools for the determination of sound power emitted by machines and other sound sources. One critical factor in the design of such rooms is the mode spacing at low frequencies. A seminal contribution to our understanding of mode spacing was made by Maa in 1939, and his paper was published in the Journal of the Acoustical Society of America. Richard Bolt also made a contribution at about the same time. In this paper, we begin with Maa's work and trace the development of mode spacing statistics through the work of Richard H. Bolt and Ludwig Sepmeyer. A computer study by the author of mode spacing statistics in 200 cubic meter rooms is described. This work led to recommendations for room dimensions to be included in an international standard on determination of sound power in reverberation rooms. Another area of interest to Maa was the sound power of sources in reverberant rooms, especially discrete frequency sources, as a function of position within the room. Some results of his work are described.