chapter
Introduction
Pages 6

The sound that is heard in most environments is a combination of the direct sound straight from the source or sources and the indirect reflections from surfaces and other objects. For instance, in room acoustics, both the direct sound and the reflections from the walls, ceiling and floor are key in determining the quality of the acoustic. To take another example, outdoors, the reflection from the ground can significantly reduce noise at certain low frequencies. Hence, one of the central topics in acoustics is how to manipulate these reflections that affect the way the sound propagates, and is ultimately perceived.