Identical reverberation times can mask drastically different room sizes and acoustics
Evidence
An interesting result from Equation 6.6 is that it appears that the level of the reverberant field depends only on the total absorbing surface area. In other words it is independent of the volume of the room. However, in practice the surface area and volume are related because one encloses the other. In fact, because the surface area in a room becomes less as its vol ume decreases, the reverberant sound level becomes higher for a given aver age absorption coefficient in smaller rooms although the reverberation time in the smaller room will always be shorter. Another way of visualizing this is to realize that in a smaller room there is less volume for a given amount of sound energy to spread out in, like a pat of butter on a smaller piece of toast. Therefore the energy density, and thus the sound level, must be higher in smaller rooms. However, there are more impacts per second with the surface of a smaller room, which gives rise to the more rapid decay than in a larger room. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1806 (
#corroborates, via linked claim)
Equations 6.17 and 6.18 show that the reverberation time depends on the volume, surface area, and the average absorption coefficient in the room. However, the absorption coefficients of real materials are not constant with frequency. This means that, assuming that the room’s volume and surface area are constant with frequency, which is not an unreasonable assumption, the reverberation time in the room will also vary with frequency. This will subjectively alter the timbre of the sound in the room due to both the effect on the level of the reverberant field discussed earlier and the change in timbre as the sound in the room decays away. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1876 (
#complicates, via linked claim)
Categorization
- XREF: connects to: Room reverberation time varies with frequency, altering perceived timbre — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1876; Smaller rooms produce louder reverberant fields but shorter reverberation times — David Howard, Jamie Angus, coustics and Psychoacoustics, 1806; Room modes produce multiple decay times instead of a single exponential reverberation — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996 (+4 more)
Broader Connections
- Smaller rooms produce louder reverberant fields but shorter reverberation times
#corroborates(0.82) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1806 - Room reverberation time varies with frequency, altering perceived timbre
#complicates(0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1876 - No reverberation-time formula has universal applicability across rooms
#complicates(0.80) - Room modes produce multiple decay times instead of a single exponential reverberation
#complicates(0.78) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1996 - Auditory expectation of reverberation is calibrated against visual room size.
#responds-to(0.75)