Reverberation time depends on room volume and surface area, not absorption alone.

Evidence

If reflecting off walls and the like causes the sound energy decay, one has only to determine how often sound hits something in a room, and then properly weigh how much sound is lost. Sound in a small room encounters more reflections per second and therefore will die out faster than in a large room made of the same materials. Heavy curtains and pillows absorb far more sound than brick walls do. A derivation of the Sabine formula for the reverberation time T60, defined as the time it takes for sound to die down in energy by a factor of a million (which is about when a loud sound fades out to inaudibility) is given in box 27.2. — Eric J. Heller, Why You Hear What You Hear- An…, 2476

Categorization

• DEFINE: Defines T60 and the reverberation-time concept that anchors the chapter’s physics.
• corroborated: 3 independent passages support this claim — Eric J. Heller, Why You Hear What You Hear- An…, 2476
• XREF: connects to: No reverberation-time formula has universal applicability across rooms; Low absorber rooms raise overall sound level because reverberant energy persists longer — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1756; Halls vary reverberation time by either adding volume or adding absorption (+4 more)

Broader Connections

• Total surface area can outweigh absorption efficiency in controlling room reverberation #corroborates (0.90) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1929
• Halls vary reverberation time by either adding volume or adding absorption #corroborates (0.85)
• Room absorption determines the steady-state level of reverberant sound #qualifies (0.80) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1781
• Reverberation time depends on both surface absorption and time between reflections #expands (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1824