The absorptive characteristics of acoustic panels in home cinema installations dramatically affect the level of early reflections heard by the listener in the home cinema seating area. The absorption coefficient of acoustic wall treatments defines the amount of energy or power that is removed from the sound when it strikes it.

In general the absorption coefficient of real materials used for acoustic treatments in home cinema systems will vary with frequency, but for the moment we shall assume they do not. The amount of energy or power removed by a given area of absorbing material will depend on the energy or power per unit area striking it. As the sound intensity is a measure of the power per unit area, this means that the intensity of the sound reflected is reduced in proportion to the absorption coefficient.

In order to calculate the intensity of an early reflection from an acoustic wall panel in a home cinema installation, we can use the formula shown below.