List Of Fiberglass, Rockwool, Polyester, and Cotton Absorption Coefficients

  • Thread starter Thread starter Diffusion
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you are the coolest member on the bbs.

i'm sorry, for some reason i can't give rep. but trust me, if i could i would give some to you every time i could for like a year for this.
 
did i mention that you were the shit?
cause i meant to.
 
I was wondering where I could find the LONG list of all of this... i found one in EXCEL format...(could it be this one?) but I wanted one in html...thanks for the link man!
 
I've noticed that the 3pcf lower density is almost universally better than 6pcf higher density, even at the lowest frequencies.
Can someone explain why this is so? Is 6pcf just so dense that is starts reflecting rather than absorbing, even 125Hz? Seems strange.
 
There is some disagreement on this. Yes. More dense materials can reflect at higher frequencies. This has to do with the gas permeability of the materials.


What is not shown in those coefficients is what happens below 125Hz. Down in the 50Hz range, the denser material will do a better job (given the same thickness and spacing).

I personally find the 3lb material to be a good compromise that is very useful for almost all applications. Dense enough to do well in the bottom but open enough to do a good job on high frequencies. Many people select this option so they are only dealing with one material in order to get better pricing on quantities and simply use an extra inch or 2 for the bass absorbers.
 
mabye there could be a sticky with this link
 
Here is a list of Knauf coefficients i just got off the company

Absorption co - efficients - S = Solid Backing - C = Cavity
Rocksilk Slabs
Thickness RS33
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
40S 0.16 0.45 0.82 1.00 1.00 1.00 0.82
50S 0.10 0.60 0.90 1.00 1.00 1.00 0.88
60S 0.22 0.75 1.00 1.00 1.00 1.00 0.94
75S 0.24 0.53 0.89 0.94 0.96 0.98 0.83
100S 0.39 1.00 1.00 1.00 1.00 1.00 1.00

Thickness RS45
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
25S 0.05 0.25 0.55 0.75 0.9 1.00 0.61
40S 0.14 0.40 0.87 1.00 1.00 1.00 0.82
50S 0.25 0.65 1.05 1.10 1.05 0.95 0.96
75S 0.50 1.05 1.20 1.15 1.10 0.95 1.13
100S 0.80 1.15 1.20 1.15 1.15 1.00 1.16
50C 0.45 0.95 0.80 0.95 0.95 1.00 0.91

Thickness RS60
25S 0.10 0.20 0.65 0.85 1.00 0.90 0.68
40S 0.13 0.49 0.95 1.00 1.00 1.00 0.86
50S 0.25 0.65 1.05 1.10 1.10 0.95 0.98
75S 0.55 1.10 1.20 1.15 1.15 1.05 1.15
50C 0.45 0.90 0.80 0.90 0.95 0.95 0.89

Thickness RS80
25S 0.06 0.23 0.56 0.88 1.00 1.00 0.67
40S 0.14 0.61 1.00 1.00 1.00 1.00 0.90
50S 0.16 0.72 1.00 1.00 1.00 1.00 0.93
60S 0.25 0.90 1.00 1.00 1.00 1.00 0.98
75S 0.39 1.00 1.00 1.00 1.00 1.00 1.00
100S 0.59 1.00 1.00 1.00 1.00 1.00 1.00

Thickness RS100
25S 0.05 0.30 0.70 0.95 1.05 1.00 0.75
40S 0.12 0.44 0.88 1.00 1.00 1.00 0.83
50S 0.35 0.85 1.10 1.10 1.15 1.10 1.05
75S 0.44 1.00 1.00 1.00 1.00 1.00 1.00
50C 0.65 0.95 0.80 0.90 0.95 1.00 0.90

Thickness RS128
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
50S 0.40 0.90 1.00 1.00 1.00 0.95 0.98
50C 0.65 0.80 0.85 0.95 0.95 1.00 0.89

Thickness RS140
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
50S 0.40 0.90 1.15 1.05 1.10 0.95 1.05
50C 0.65 0.80 0.85 0.95 0.95 1.00 0.89

Thickness RS200
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
50S 0.40 0.50 0.70 0.70 0.70 0.70 0.65

Rocksil Insulation Mat
Thickness
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
150 0.70 1.20 1.24 1.13 1.14 1.18 1.18
100 0.40 0.88 1.03 0.99 1.06 1.11 0.99
80 0.31 0.83 0.96 0.98 1.04 1.14 0.95
60 0.25 0.60 0.83 0.89 0.96 1.04 0.82

Rocksil Studio Mattress
Thickness
125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz NRC
50S 0.25 0.65 1.05 1.10 1.05 0.95 0.96
50C 0.45 0.95 0.80 0.95 0.95 1.00 0.91
S= Solid Backing - C = cavity
 
The best suited for me is the RS45 100S, but it does dip quite a bit at 125Hz. Would a better solution be to get the RS128 50S, and double it up?
 
I went to Home Depot earlier today and saw "Fiberglass Insulation." It's not rigid fiberglass, so would that do fine for using in the production/mixing room? I forgot the brand of it, though!! :( I'll go check it out tuesday to see the brand. It was 2" thick though and yellow.
 
Nice thread!!
I have a question. I'll be buying a rockwool board with a density of 50kg/m3 and dimensions of 100mm 4" x 2' x 4'. Will the density of 50kg/m3 be "ok" for the use in sound absorption?
 
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