Engineering Geometrical Acoustic Method for Higher-Order Diffraction of Sound in Building

Calculation of noise in the environment has been the subject of research for many years. Modern noise standards are based on simple algorithms of the "sound ray detour" method, which is implemented in ISO 9613-2, the most common standard used in Russia and Europe. The method of "detour" can be used without a special program. However, it can generate non-physical effects in the expected sound fields. The Nord2000 standard uses advanced wave-based diffraction procedures, but it is limited to two diffraction events and also causes some uncertainty in the prediction. Geometric acoustic methods are easier to implement and do not require large computer resources.Here we demonstrate an improvement of a standard "detour" method due to implementation of an energy transmission mechanism from the noise source to a secondary and higher order sources. We also present comparison of results with other calculation methods and results of measurements that demonstrate a good agreement of the proposed method to the reality.