Smaller rooms produce louder reverberant fields but shorter reverberation times
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
In fact, because the surface area in a room becomes less as its volume decreases, the reverberant sound level becomes higher for a given average 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 M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1767
Categorization
- XREF: Connects to the butter-on-toast energy-density analogy for explaining acoustic phenomena to non-specialists; resonates with how the reader uses psychoacoustic concepts to interpret spatial experience. — connects to: Sabine experimentally verified exponential sound decay in a reverberant room; Identical reverberation times can mask drastically different room sizes and acoustics; Recommendable reverberation times range from 2 seconds down to 0.35 seconds by room type (+11 more)
- CANDY: The butter-on-toast analogy makes the smaller-room-louder-reverb point instantly graspable; great idle conversation nugget.
- corroborated: 5 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1806; David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1767
Broader Connections
- Reverberant fields supply most perceived loudness in normal rooms
#contradicts(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1776