A room mode’s length relative to mean free path sets its decay time

Evidence

The decay of sound energy in the room is no longer a single exponential decay with a time constant proportional to the average absorption in the room. Instead, there are several decay times. The shortest one tends to be due to the diffuse sound field, whereas the longer ones tend to be due to the resonant modes in the room. This results in excess energy at those frequencies with the attendant degradation of the sound in the room. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996 (#expands, via linked claim)

Categorization

• XREF: connects to: Modal decay time depends on mode length relative to the diffuse-field mean free path; Room modal bandwidths depend on decay time, not frequency — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2012; Room modes produce multiple decay times instead of a single exponential reverberation — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996 (+1 more)

Broader Connections

• Room modes produce multiple decay times instead of a single exponential reverberation #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996
• A slowly-decaying frequency makes a room ring at that pitch #expands (0.82)