INDOOR REVERBERATION TIME MEASURING METHOD

摘要

PURPOSE:To select automatically a time interval, and to execute exactly a measurement by executing sampling by a sampling period until reaching a reference value of a sound pressure level from a time point of stop of a testing sound, and calculating a reverberation time. CONSTITUTION:A sampling time interval DELTAt and the number of inputs B of sampling data are determined by a pre-measurement. The inside of a room 1 is set to a diffusion sound field by driving a loudspeaker 2, in a state that band pass filters 5, 7 remain set to a frequency band selected by the pre-measurement, and subsequently, the loudspeaker 2 is turned off. After that time point, sampling data from an A/D converting circuit 10 is inputted by DELTAt and B until a measured sound pressure of a microphone 3 becomes a reference value (Lu+alpha+sigma). Such a data input is executed by a prescribed number of times, and a reverberation time of the inside of the room 1 is calculated.