ABSTRACT
This chapter develop analytical methods for predicting the propagation characteristics of noise both in outdoor and indoor environments. In addition, methods to account for the influence of reflecting surfaces, partial barriers, and meteorological and topological conditions will be presented. In the case of reverberation rooms, they are always large, and the walls, floors, and ceilings are highly reflective, usually of heavy masonry construction. The resultant sound field in the reverberation room is very diffuse; that is, the sound is a complex combination of reflected sound. Partial barriers occur frequently in both indoor and outdoor environments. Sound waves propagating over a partial barrier are diffracted, producing a shadow zone of generally diminished sound amplitude. The propagation of sound outdoors, at distances of several hundred feet or more, is often significantly affected by atmospheric, meteorological, and ground cover conditions. Vertical differences in temperature and wind velocity are generally present in the lower boundary of the earth's atmosphere.
