Uncertainty of measuring reverberation time at low frequency in a residential building

Abstract

Although the reliability on the measurement results of floor impact sound is important, high large variation of reverberation time in receiving rooms might result in high uncertainty at the low frequencies. Reverberation time at low frequencies is influenced by the arrangement of furniture and position in the receiving room. In this study, the effect of furniture arrangements on reverberation time in a receiving room was investigated in the apartment buildings. Heavy-weight impact sounds level generated by bang machine and impact ball were measured to estimate the effect of furniture arrangement. The results show that the standard deviation was relatively greater at 63 Hz frequency band. Small variance at 63 Hz was measured in terms of furniture arrangements. Variation of the measured single number rating of Li,Fmax, AW ranged from 1 to 4 dB according to the absorption power of furniture. The reasonable number of measurements was suggested based on the uncertainties of reverberation time at 63 to 500 Hz.