section 6 discusses the behavior sound indoors. the foundation for this discussion was laid in section 5 (Sound Outdoor)
In comparison with its behavior in free field, sound indoors exhibits quite complex behavior. Decades of acoustics research have been spent attempting to quantify the effects of reverberant field. These efforts have yielded a body of equations that are used to describe how sound behave in given room. we make no effort to present those calculation in detail here. such effort would not serve our present purpose. Instead, this cheaper presents the basic principle of indoor acoustics, using simple mathematics where necessary