The absorption coefficient measures the fraction of incident sound energy absorbed.

Evidence

The fraction of sound energy that is not reflected is absorbed from the sound field of the first medium. The ratio of absorbed energy to the incident energy is called the absorption coefficient. When the reflection of the wave is described by the coefficient R, as defined in Equation (2.25), the absorption coefficient a is obtained from the equation Refraction is the phenomenon of the wavefront bending when entering a medium with a different sound velocity. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 257

Categorization

• DEFINE: Defines the absorption coefficient, a core quantity in room acoustics and acoustic design.