Schematic representation of the forward masking pattern (dashed) from [30] (p. 83, Fig. 4.22) as a function of the delay time log(ΔT) together with nominal amplitudes of specular and diffuse reflection (solid) as a function of time t. The masker (direct sound) ends at t = 0 ms. The masked level is achieved, if reflection’s envelope peaks exceed the post masking pattern. For the specular reflection this when the reflection ends at ΔT, whereas envelope fluctuations of the diffuse reflection exceed the level of masking in the time range of ΔT _M.