Air absorption is negligible in small rooms but overbrightens artificial reverberation

Evidence

This coefficient is shown at the bottom of Table 6.1, and from it one can see that for small rooms, the effect can be ignored, because until the volume becomes greater than 40 m3, the equivalent absorbing area is less than 1 m2. However, the effect does become significant if one is designing artificial reverberation units because, if it is not allowed for, the result will be an overbright reverberation, which sounds unnatural. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1946

Categorization

• DEFINE: Clarifies ‘air absorption coefficient’ by quantifying when it matters — below 40 m3 room volume the equivalent absorbing area stays under 1 m2.
• XREF: Connects to any prior chapter material on sound absorption coefficients and Sabine reverberation calculations. — connects to: Air absorption must be modeled or artificial reverb sounds overbright — David Howard, Jamie Angus, coustics and Psychoacoustics, 1987