Each surface reflection removes a fixed fraction of sound energy.

Evidence

Equation A4.2 gives us the time between surface interactions, and at each of these interactions α is the proportion of the energy absorbed, where α is the average absorption coefficient discussed earlier. If α of the energy is absorbed at the surface, then (1 − α) is the proportion of the energy reflected back to interact with further 480 APPENDIX 4: Deriving the Reverberation Time Equation surfaces. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2820

Categorization

• DEFINE: Clarifies α as the average absorption coefficient and connects it to the fraction reflected.