The receiving points used for measuring floor impact sound levels are specified as follows: “Within the receiving room, distribute four or more measurement points evenly, each separated by at least 70 cm, with spaces at least 50 cm away from the ceiling, surrounding walls, and floor surface.” The energy-averaged sound level over these points is used for evaluation. The present letter verifies whether this averaged value sufficiently represents the floor impact sound levels throughout the receiving room. Using the finite-difference time-domain method, a two-story concrete building was analyzed. The floor impact sound levels were compared between a case where multiple receiving points were installed and a case where only the receiving points specified by the standard were installed. The comparison confirmed that while differences exceeding 5 dB were observed in several frequency bands, the specified points sufficiently represent the floor impact sound level with adequate accuracy across a broad frequency range, including the decisive frequency.
Masahiro Toyoda (Thu,) studied this question.