(Alternatively we could say that GG improved the performance by 10dB using a different pair, but then I'd claim that we should use the 10dB difference in doubling mass that I found below - so let's continue comparing apples to oranges and just go with it) So, just for the sake of a bit of math, let's say that that GG improves the 50hz to 63hz performance by 6db, using the bold lines I compared above. Not one of those gets near the GG's advertised Here's a few double stud walls from IR761, which are a different lab, a different day, in a frequency range they don't certify, but Brian didn't provide comparisons or even wall specifics in that post either, although I think he did provide a little more detail somewhere else, nevertheless so lets compare apples to oranges.ĢG16_SS65(610)_GFB65_AIR20_SS65(610)_GFB65_2G16ĢG16_SS40(610)_MFB40_AIR65_SS40(610)_MFB40_2G16ĢG16_WS90(610)_GFB90_AIR25_WS90(610)_GFB90_2G16ĢG16_WS90(610)_AIR25_WS90(610)_CFS60_2G16 There is 3rd party data from NVLAP labs for a 2x4 wall assembly (STC 56, 24/25 dB of TL at the low frequency resonance point, relatively superb performance compared to alternate options), and for a double stud wall (32/36/35 dB of TL at 40/50/63hz, as far as i know the best stud wall ever tested) I don't remember the cost of green glue 100% coverage of an 8'x8' wall. There are more effective CLD products, but they are as far as I know either really toxic or hard to install or very expensive. It can't be used until your wall has at least three layers (2 layers of drywall on one side with GG between, and one layer of drywall on the other side).Ĭertainly GG is more cost effective than other CLD products. So the question is, where is green glue more cost effective than just adding more drywall. So it has three good pointsĪ) it reduces the resonance dip, by increasing the absorbtion of the wall when it movesī) it damps the sound traveling along the panelĬ) it doesn't use up any room space or weight. Going from 8 layers to 16 layers, well, that's just silly. Going from 4 layers to 8 layers is more expensive. Going from 2 layers of drywall to 4 layers of drywall isn't that expensive. There's a rule for walls that says doubling the mass gives 6dB more isolation. Whereas 1/2" drywall is almost twice that mass. It's, by definition, heavy, so shipping might be interesting.ġ20 square foot = 11.1483648 square meterġ Great Britain Pound = 1.834 US Dollars, so Says 4'x30' of Auralex Sheetbloc Plus is $399 not including taxes and shipping. As I recall, the thinking on MLV is thatĪ) in the middle of the cavety it's a triple leaf thing (bad).ī) but between layers of drywall it adds mass (good), it's a different density (good to lessen the coincidence dip), it's thin (good), a 40' long roll of it helps in air tightness (good), some have glued it to the next piece giving more air tightness(good), it's more expensive than drywall (bad). So if I were chosing between the two it would be Green Glue. Audio Alloys has the lab data to back that up. I haven't measured yet but I'm inclined to say that the Green Glue is clearly better than the mass loaded vinly. Now you can still hear it but it sounds like its coming from outside as the sound is escaping through the windows and you hear it thorough the bedroom windows instead of the floor. What I've noticed now is that before you could hear the theater sound coming through the floor of my two story home. However, since I've added the Green Glue, the wall is even better. With this my wall measured -22db at 50hz, -16db at 63hz, -26db 80hz, and -28db at 100hz on the other side of the wall in my garage. My wall was first 1/2 dry wall, mass loaded vinly, R-13 insulation and then 1/2 drywall. Although, I've read and been told that mass loaded vinly only give a 3 db reduction to the wall, that's not what my sound meter reads.
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