Halls vary reverberation time by either adding volume or adding absorption

Evidence

Table 6.3, Figure 6.20 and Figure 6.21 show the effect of applying the treatment, which dramatically improves the reverberation time characteristics. The reverberation time now only varies from 0.59 to 0.41 s, which is a much smaller variation than before. The peak-to-peak variation in the level of the reverberant field has also been reduced to less than 2 dB. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1944 (#exemplifies, via linked claim)

Clearly the length of time that it takes for sound to die is a function not only of the absorption of the surfaces in a room but also of the length of time between interactions with the surfaces of the room. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1824 (#expands, via linked claim)

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)

Categorization

• XREF: connects to: Concert hall reverberation times range from one to two seconds; Low absorber rooms raise overall sound level because reverberant energy persists longer — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1756; Sabine’s 1898 formula made reverberation time the dominant auditorium design parameter (+5 more)

Broader Connections

• Reverberation time depends on both surface absorption and time between reflections #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1824
• Targeted absorber addition flattens reverberation time variation across frequencies #exemplifies (0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1944
• Room absorption determines the steady-state level of reverberant sound #expands (0.80) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1781
• Physical sound absorption can be strong enough to measurably alter room reverberation #exemplifies (0.80)