Abstract
When measuring the sound absorption coefficient of materials in a reverberation room, changes of the temperature and relative humidity in the room before and after setting a test specimen can cause considerable errors especially in high frequency bands. In order to investigate the correction method for such kind of error, numerical and experimental investigations were made in this study. At first, the calculation method for the correction was investigated, and then, possible errors due to atmospheric condition change were numerically examined based on the calculation method of the sound intensity attenuation loss of air prescribed in ANSI S1. 26-1978. As the experimental investigation, a set of reverberation time measurements were made in a reverberation room, with and without a sound absorption material, under various atmospheric conditions. From those results, the sound absorption coefficients of the material were calculated by considering the effect of atmospheric sound absorption. As a result, it was found that fairly consistent values of the sound absorption coefficient can be obtained by making the correction for atmospheric sound absorption even if the temperature and relative humidity conditions vary greatly.
