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1.3.2 Detailed Sound Measurements > 1.3.2.1 Sound Persistence in Enclosed Space... - Pg. 12

12 SecTion | 1 Test and Measurement to the audience. Part of the role of the measurer is to determine if the response of the loudspeaker or room is inhibiting the required system performance. 1.3.2.1 Sound Persistence in Enclosed Spaces Sound system performance is greatly affected by the sound energy persistence in the listening space. One metric that is useful for describing this characteristic is the reverberation time, T 30 . The T 30 is the time required for an interrupted steady-state sound source to decay to inaudibility. This will be about 60 dB of decay in most auditoriums with controlled ambient noise floors. The T 30 desig- nation comes from the practice of measuring 30 dB of decay and then doubling the time interval to get the time required for 60 dB of decay. A number of methods exist for determining the T 30 , rang- ing from simple listening tests to sophisticated analytical methods. Fig. 1.5 shows a simple gated-noise test that can provide sufficient