Green Glue...

I thought about using it, but it was cheaper to just use more drywall layers, so that's what i did.

It's an elastomeric liquid that cures sort of soft and dampens the vibrations between the panels, much like the sound control sheets they put in cars.

Also, you aren't blind or dull, there has always been very little information on actual testing of this stuff with most of the information being anecdotal.

I did find some random forum threads about folks using it and getting only a little iimprovement, with those selling it quickly swooping in to proclaim that it must not have been applied correctly, with the thread disappearing shortly thereafter. Take that as you will.

If you're going to try this Tony, the way in which it is installed is a very very precise process. One little mistake, or deviation from their recommended specs and it basically ruins the whole thing. Basically it has to be put on with specific bead height and width, and when it's all done is like a giant interconnected network that distributes the vibrations all through the network to cancel them. Like others have said, one run away screw, or gap in the bead and all that money is burned into thin air.... poof.

With that said, if you follow the rules and do it right, nothing can beat that stuff, it's genius.

Thanx Fella's, to be clear, i'm a construction contractor by trade, i've built a dozen sound proofed rehearsal spaces and studio's in my time. I've always used the multiple layers of 5/8" sheetrock method(1/2" is useless) and it works great, but if greenglue's claims are true, it's cheaper to use it, than 2 more layers of 5/8" rock, not to mentioning the physical and financial toll of installation, and loss of space.
  The 3 proven tenets of sound proofing are mass, decoupling, and air sealing. In the case of decoupling, one screw in the wrong spot short circuits a system and renders it useless, so when using RC8 (resilient drywall channel), one screw through the rock/channel and into the wall or stud behind it, renders the system a recoupled fail, as it now transmits vibration.

My question is more about how greenglue achieves what it claims(damping in place of mass), and where is the comparative before and after data located that proves it's claims?

My studio is all green glue which was recommended by the local guru.

gg works better than not using it on freq above bass regions. So it scores higher on the averaged sound reduction figure. Where it falls down is bass freq. It does not perform better there. Unless the product has been reworked since the test data i remember from when i designed my studio.

it is particularly effective in existing fitouts because you gain decoupling without lose of floor space and only get the negative 3 leaf effect on the really low freq. Like below 150hz.

if i were building from scratch i wouldn't use it. You will be hard pressed beating a double wall setup with 2 layers of high density sheeting and insulation per leaf.

Me personally, I wouldn't use or specify any material unless it comes with test data. It is not worth wasting money on.

most acoustic materials aren't rated for bass freq because they are sold specifically for commercial and industrial use where the freq of concern are more low to upper mids.

to be honest, i'm wary of this product, 1st i'm a licensed GC, i've been at this for 25 years, i'm not easily fooled. i've been trying to find explanations of how this stuff works today, and i'm having to search too hard, generally if something is legit, it's easy to get plenty of data on it's efficacy, snake oil usually comes in mysterious claims of grandeur, what i was able to realize, is it has poor performance at low frequencies, the main reason for me to use it.

keymod i'm not sure of any roofing that contains zero asphalt? I know that dynamat has no asphalt, and is butyl based, but talk about expensive! I can tell you that any membrane that remains supple between layers of drywall will damp, to what degree and the differences being worth a shit between materials? i can't be sure. I do KNOW that with proper installation, multiple layers of rock, with air tight joints and decoupling are going to work every time.

the whole "use 3 huge tubes of greenglue per sheet" @$20 a tube really fucked me off smh.

i could still change my mind if the legit data was put under my nose.

Fair enough Ward I also would echo your sentiments about is likely being snake oil. My understanding of isolation is that it has to be room within a room and I can't imagine that a glue is going to tame low end but I don't know anything about the product whatsoever, I've just read stuff on forums about it. I think one of the big studios in town did their construction with it but I've never been there.

My understanding is GG is a damping compound and not a soundproofing compound.
I agree that GG is expensive. But what's the cost and weight of 2 extra layers of drywall.
Let alone the cost of labor to install the 2 extra layers. I don't think ceiling or wall iso clips
can even support 4 layers.
I used GG between the extra layer of drywall I applied to the outer shell of the new tracking room
and I can hear the damping effect when hitting the walls. The inside walls will have iso clips, hat channel,
and 2 layers of dry wall with GG. Double walls are not possible. No green glue is not the solo answer
to soundproofing but only a part of a system in the quest for noise reduction, that I'm willing to pay.



 

i guess that 2 layers with gg is claimed to be = to 4 without, but not on the low end, which is the only reason to use 3 to 4 layers of 5/8" IMV

Thanx Eric, that link is on my first post, I'm looking for the baseline for comparison...haven't found it.

Ah
Yeah that's all they seam to have, for the money I think I would go with either a traditional limp mass or more layers of dry wall!
It would be interesting to see what this stuff is like 10-12 years down the line .
I know people who swear by it but I haven't used it.
I also wonder How it works with calked joints. I always worry about, the area where you know there could already be problems!

You stagger the joints on the drywall layers and only need to caulk the seams of the last layer,
using tape and mud or Acoustic caulk and tape. You also leave a 1/8" to 1/4" gap around the edges and fill those in with foam rope and then acoustic caulk on top of that.
GG also makes a none harding acoustic caulk for these purposes.