Abstract
An extended energy integral equation method has been developed for precise predictions of noise propagation in and around a multi-room building surrounded by other buildings. In this method, all energy flows between boundary elements of the calculation model are obtained by solving equations considering multiple reflections, multiple diffractions and sound transmission. In order to improve the precision of the method, the calculation of first reflections is separated from the calculation of multiple reflections, and the first reflections are calculated by the approximated method derived from the wave theory. This method is applied to the calculation of sounds transmitted through small openings. Predictions using these methods corresponded well with measurements from actual sound fields.
