Comparing measured sound strength to theory as a function of reverberation time and room volume

Abstract

ISO Standard 23591 demonstrates how the sound pressure level in a room may be estimated with a knowledge of (1) the sound power of sources in that room and (2) the sound strength G of that room as defined in ISO 3382-1. In this presentation, the theory connecting room volume V, reverberation time T60, and sound strength G is summarized, and a comparison of measured sound strength G to this theory is explored for a wide range of rooms. After an explanation of the mathematical model, a description of the calibration of measurement equipment using Odeon software is discussed, including measurements taken in a reverberation chamber. A brief review of the rooms in which sound strength was measured is provided. Both measured and theoretical sound strength results are presented for the rooms reviewed. The difference between measured G and theoretical G using this mathematical model is analyzed statistically both for data measured with this test setup and with concert hall data from Beranek’s book. This model lends itself to designing rooms of appropriate reverberance and loudness for a given context, musical or otherwise.