Absorption Coefficients of Acoustical Materials

Rickster71

Rickster71

Audioholic Spartan
Hope this wasn't posted already.:)

If anyone's thinking of DIY acoustic panels or bass traps here is a good site with the (Brand Listings) Absorption Coefficients of Fiberglass, Rockwool, Polyester, Cotton.


http://www.bobgolds.com/AbsorptionCoefficients.htm

0.00 = no absorption.
0.50 = 50% absorption.
1.00 = 100% absorption.
 
nibhaz

nibhaz

Audioholic Chief
More DIY Info

Here is the link to the Porous Absorber Calculator.

I know I’ve linked this elsewhere, but I think it’s a valuable tool which is worth repeating.

It will let you model various combinations of panel width, air gap, and material type.

Personally, I would figure out which materials are available in your area first and then start modeling. In order to compare various materials you’ll need to know the gas flow resistance (GFR) of the material measured in mks rayls/m.

I’ve compiled a list of values for commonly used materials. The only caveat is that these values are merely estimates. The actual values change from time to due to manufacturing variances.

Corning 701 8,300 mks rayls/m
Corning 703 16,000 mks rayls/m
Corning 705 30,000 mks rayls/m
"Mineral Fibre (M2)”, average density 44.2 kg/m^3 GFR 16,000 mks rayls/m
"Mineral Fibre (M3)", average density 98.1 kg/m^3 GFR 58,000 mks rayls/m.\
Roxul AFB 2.8 pcf: 3” thickness – 16,600 mks rayls/m
Roxul AFB 2.8 pcf: 1.5” thickness - 15,000 mks rayls/m.

Also note that the calculator only gives values for a single angle of incident, so you’ll want to adjust the angle of incident for of each of your models to get a better idea of how they will perform in an actual room filled with random incidents.
 
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