Very dead rooms lack a true reverberant field entirely

Evidence

The very short reverberation times that occur when the absorption is high pose an interesting problem. Remember that one of the assumptions behind the derivation of the reverberation time calculation was that the sound energy visited all the surfaces in the room with equal probability. For our example room, the mean time between reflections, using Equation 6.16, is given by: … These are barely enough reflections to have hit each surface once! In this situation, the reverberant field does not really exist; instead, the decay of sound in the room is really a series of early reflections to which the concept of reverberant field or reverberation does not really apply. In order to have a reverberant field, there must be much more than six reflections. A suitable number of reflections, in order to have a reverberant field, might be nearer 20, although this is clearly a hard boundary to accurately define. Many studios and control rooms have been treated so that they are very “dead” and so do not support a reverberant field. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1849

Categorization

• DEFINE: Clarifies the boundary condition for what counts as a reverberant field: roughly 6-20 reflections minimum.
• XREF: connects to: Non-environment rooms kill the reverberant field while keeping early reflections for occupants — David Howard, Jamie Angus, coustics and Psychoacoustics, 2294