Sabine’s reverberation formula founded architectural acoustics but fails for high absorption

Evidence

If a steady tone, such as an organ note, is played in the space then after a period of time the reverberant sound will reach a constant level because at that point the sound power input balances the power lost by absorption in the space. This means that the steady-state level will be higher in rooms that have a small amount of absorption, compared with rooms that have a lot of absorption. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1781 (#expands, via linked claim)

The amount of sound energy available for contribution to the reverberant field is also a function of the absorption, because if there is a large amount of absorption, there will be less direct sound reflected off a surface to contribute to the reverberant field-remember that before the first reflection, the sound is direct sound. The amount of sound energy available to contribute to the reverberant field is therefore proportional to the residual energy left after the first reflection, Reverberant level is that which allows input to equal output FIGURE 6. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1763 (#expands, via linked claim)

Categorization

• XREF: connects to: Sabine experimentally verified exponential sound decay in a reverberant room; The Sabine formula assumes diffuse sound that real rectangular rooms rarely produce; Sabine’s 1898 formula made reverberation time the dominant auditorium design parameter (+5 more)

Broader Connections

• Room absorption determines the steady-state level of reverberant sound #expands (0.80) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1781
• No reverberation-time formula has universal applicability across rooms #qualifies (0.80)
• Room modes produce multiple decay times instead of a single exponential reverberation #complicates (0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996
• Higher absorption reduces the first-reflection energy that feeds the reverberant field #expands (0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1763