Reverberation and Effective Absorption in Rooms with Diffuse Wall Reflexions

Firstly on the basis of a rather general description of the decay process it is shown in this paper, that the Eyring reverberation formula is not generally valid if the wall absorption is non-uniform. A more exact, though not closed computation procedure, however, leads to good agreement with the decay times obtained by the application of a Monte-Carlo-method. The influence of nonconstant free-path lengths can be accounted for by a simple correction.

As being more useful for the purpose of practical application, a correction term to the Eyring formula is derived, by which the decay time of polyhedral rooms with non-uniform absorption can be calculated fairly exactly.