A microphone multiplexer for the measurement of the space average of sound levels

Many of the acoustic measurements performed in rooms require that the space average sound pressure level be measured. In the system described in this paper, a fast scanning microphone multiplexer and a true RMS level detector are used for obtaining a direct reading of the SPL space average. The optimum scan rate (channels/sec) is dependent upon the number of microphones (between two and seven), the frequency, and the filter applied.