ABSTRACT
This chapter explains the negative aspects of an isolation shell. It discusses the basic wave acoustics. The chapter examines the pressure and velocity components of sound waves. It also shows an important point which relates very much to control room acoustics. When a sound source in a highly reverberant environment emits an acoustic wave, the wave initially expands according to normal free-field expansion, but before the sound reaches the first boundary the conditions are, by definition, anechoic. The pathways available for a sound wave to travel around a room are known as modes, and in any room they are infinite in number. There are three types of resonant mode in a rectangular room. These consist of axial modes, tangential modes, and oblique modes. The most important controlling factor in room acoustics for recording studios is absorption. Reverberation is a much misunderstood concept, at least in terms of its relevance to rooms of the size encountered in most recording studios.
