Development of a delayed coupled room model for the prediction of the performance of early energy decay in churches

To study the performance of early energy decay in churches, acoustical measurements under an impulse excitation were conducted in a Protestant church and a Catholic church in Hong Kong. The results show that the coupling effect is more prominent than the effect of the source-receiver distance in Barrens model. Moreover, a delayed coupled-room model was developed. It introduces geometrical acoustics into statistical acoustics to verify a diffused sound field condition, and modifies the initial condition in the impulse duration by introducing a delayed time interval for sound propagated from the source to achieve diffuse sound fields in each subspace. The predicted results of the coupled room model agree well with the measured ones.