Air absorption must be modeled or artificial reverb sounds overbright

Evidence

As the effect of air absorption is determined by the distance the sound has traveled, rather than its interaction with a surface, it is difficult to incor­ porate the effect into the reverberation time equations discussed ­ earlier. An approximation that seems to work is to convert the effect of the air ­absorption into an equivalent absorption area by scaling an air absorption coefficient by the volume of the space. This is reasonable because as the vol­ ume of the room increases, the more air the wave must travel through and the longer the distance that it travels. 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 Howard, Jamie Angus, coustics and Psychoacoustics, 1987

Categorization

• XREF: Connects to the reader’s interest in applying psychoacoustics methods - this is a concrete design failure mode (overbright artificial reverb) from ignoring air absorption. — connects to: Air absorption is negligible in small rooms but overbrightens artificial reverberation — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1946; Air absorption and room acoustics can be modeled as low-pass and arbitrary filters — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 416; Air absorption of high frequencies makes distant voices sound duller — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1943 (+2 more)

Broader Connections

• Air absorption is negligible in small rooms but overbrightens artificial reverberation #qualifies (0.92) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1946
• Air absorption in rooms under 40 cubic meters is acoustically negligible #qualifies (0.88)
• Air absorption of high frequencies makes distant voices sound duller #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1943
• Air absorption and room acoustics can be modeled as low-pass and arbitrary filters #expands (0.78) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 416
• Reverberant fields typically color perceived sound with excess bass that equalization must fix #corroborates (0.76)