本文
No.7(2004)8.Measurement system test that predicts the reverberation time in an empty reverberation room
Osamu NAKATA, Koichi KANDA
The standard sample is not defined in measurement of sound absorption coefficients in a reverberation room. Instead of using a standard sample, the sound absorption coefficient is defined by the difference between two reverberation times when a specimen is placed in a reverberation room, and when it is not placed. The judgment methods of whether a measurement system is normal or not are the checking of the operation of instruments under measurement, investigating the measurement results, etc. This paper describes a synthetic test method of the condition of a measurement system. The method is to predict the reverberation time in an empty reverberation room which changes according to temperature and humidity, and to compare the predicted value with an actual measurement. In order to realize this, the sound absorption effect of an empty reverberation room was expressed with an equation. Then, the reverberation time was predicted with a 3% degree of accuracy to arbitrary temperature and humidity. Thus, it became possible to test the conditions of the measurement system synthetically.
Keywords
Reverberation time, Sound absorption coefficient, Reverberation room