Effects of damping on the low-frequency acoustics of listening rooms based on an analytical model

A study of the effects of damping on the low-frequency acoustics of listening rooms has been undertaken. The study was carried out using a new numerical implementation of an analytical solution based on a model developed by Bistafa and Morrissey. The model was designed to simulate the sound field in rectangular enclosures below the Schroeder cut-off frequency. Four hypothetical rooms were studied, a lightly damped room, a well damped room, a statistically compliant European Broadcast Union control room and a compliant European Broadcast Union control room. The most important result from the study using the proposed model was the influence of modes above the Schroeder cut-off frequency on reverberation time. This was caused by the variations in damping between mode types and variations in the modal coupling between the source and receiver. The research suggests that Schroeder's 1954 cut-off frequency for the influence of modes was more correct for highly damped rooms, in comparison with the Schroeder's 1964 relation.