jbassino wrote:
Any of you guys know or have any information regarding panel absorbers?
Im wishing to have real life tests of how many frecs and how much of them lets say one 4" deep panel absorbs. (I'm not talking about coef absorption values that many website offer. if not, how much RT60 is reduced by an X amount of absorption placed and how many DBs that will change)
If none is available, I'm willing to do the tests my self including:
- Placing panels against the wall
- Spacing the panels 10cm from the wall
- Triying different density on wool used (18, 36 and 80kg/m3)
- etc
Thanks
Pardon me for waking an aging thread . . .
The old rule of thumb that you are seeking [every doubling of absorption results in 3dB reduction] certainly is appealing. Unfortunately, it's only valid for diffuse, large, low-absorption spaces - the spaces in which the Sabine equation works very well. Since few rooms DIY'ers deal with meet these criteria, it's pretty hard to equate # panels to decibels.
However, if you've managed (by the various other calculation methods out there) to get a reasonable estimate of the reverb change in question, you can estimate the dB reduction by the simple inverse-square rule. Essentially: for every halving of RT60, you will see approx -3dB.
Caveats/factors to consider:
--DB Reduction assumes measurement at a location greater than the critical distance.
--Critical distance varies with RT
--"Reverberation" in the classic sense is not possible in rooms that are small, or oddly proportioned, or highly damped --The soundfield is never fully diffuse, and decay levels/rates are not constant throughout the space.
The latter point is why it's so tricky to predict the decay/reverberation of typical studio builds in the first place.
--- Mark