Comparison of measurement methods of room sound energy for sound insulation performance evaluation at low frequencies

In the field measurement of acoustic performances, such as sound insulation and floor impact sound insulation, sound pressure level is usually measured to find the sound energy in a closed space. However, the sound pressure level at low frequencies such as the 63 Hz band depends on the measurement position due to the influence of the room eigenmodes, which leads to large uncertainties of the measured average sound pressure levels in rooms. In this study, several measurement methods of sound energy were applied to the low-frequency sound field of a mock-up room that simulates a source room in an RC apartment. Along with the standard sound pressure level measurement, the low-frequency procedure according to ISO 16283 series and acoustic energy density measurement using the combined particle velocity-pressure sensor were conducted, and their accuracies were evaluated based on the average sound pressure obtained by the grid-point measurement over the entire room.