A single slope measurement of dB decay directly yields the reverberation time

Evidence

W. C. Sabine, the acoustician, has defined reverberation time technically. It is the time that elapses from the instant a sound source is switched off until its energy decays to one millionth of its original strength (a drop of 60 decibels). As far as the ear is concerned, it is the time it takes for a sound to melt and be lost in the ambient noise. Echo differs from reverberation in that it is a repetition or partial repetition of a sound, due to reflection off a distant surface. Reverberation is also reflected sound but no separate repetitions of the original are distinguishable. — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 446 (#expands, via linked claim)

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 (#qualifies, via linked claim)

Categorization

• XREF: connects to: Sabine experimentally verified exponential sound decay in a reverberant room; Reverberation time is defined as a 60-decibel energy decay — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 446; Room modes produce multiple decay times instead of a single exponential reverberation — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996 (+3 more)

Broader Connections

• Reverberation time is defined as a 60-decibel energy decay #expands (0.90) — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 446
• Room modes produce multiple decay times instead of a single exponential reverberation #qualifies (0.78) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996
• Ideal reverberation is a smooth exponential decay whose rate depends on context. #qualifies (0.75)
• Room modal bandwidths depend on decay time, not frequency #complicates (0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2012