Reverberation time formulas rest on statistical assumptions about sound fields
Evidence
Equation 6.17 is known as the “Norris–Eyring reverberation formula;” the negative sign in the top compensates for the negative sign that results from the natural logarithm resulting in a reverberation time which is positive. Note that it is possible to calculate the reverberation time for other ratios of decay and that the only difference between these and Equation 6.17 would be the value of the constant. The argument behind the derivation of rever beration time is a statistical one and so there are some important assump tions behind Equation 6.17. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1866
The argument behind the derivation of reverberation time is a statistical one and so there are some important assumptions behind Equation A4.10. These assumptions are: n that the sound visits all surfaces with equal probability, and at all possible angles of incidence; that is, the sound field is diffuse. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2825
Categorization
- DEFINE: Establishes what the Norris-Eyring formula is and why its derivation is statistical, which anchors how reverberation time is computed.
- XREF: Connects to the earlier Sabine derivation in the same book — both rest on averaging assumptions that limit when the formula holds.
- corroborated: 3 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1866; David Howard, Jamie Angus, coustics and Psychoacoustics, 2825