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Sound deadening my media room - a little DIY - Page 2

post #31 of 53
Thread Starter 
Appreciate the video upload. The GG makes all the sense in the world, especially versus nothing. It essentially acts as a shock absorber between the 2 layers, creating a good deal of friction if you will. (this is not a perfect analogy, so dont get all worked up over it, but it's close enough for the layman) One can presume that GG was designed to have the best sound-to-heat translation versus ordinary caulk or silicone. It costs less as well, so if you're serious about sound deadening and you're doing 2 layers of drywall, you may as well do it.

I'd personally like to see sound translation between 2 layers of drywall with GG versus 2 layers of the same drywall with silicone caulk, and again with latex caulk. GG's MSDS claims it's a latex polymer mixed with water, so I'm assuming its results would be very similar to latex caulk, but I'd like to see how much different.

And then 2 layers of other rigid objects like metal sheets, plywood, etc, just for scientific purposes.
post #32 of 53
Quote:
Originally Posted by Adoniram View Post

I'd personally like to see sound translation between 2 layers of drywall with GG versus 2 layers of the same drywall with silicone caulk, and again with latex caulk. GG's MSDS claims it's a latex polymer mixed with water, so I'm assuming its results would be very similar to latex caulk, but I'd like to see how much different.

And then 2 layers of other rigid objects like metal sheets, plywood, etc, just for scientific purposes.
That sounds like an excellent experiment for an up and coming scientist. Let us know the results of your study! wink.gif
post #33 of 53
Quote:
Originally Posted by hagbard72 View Post

Sounds like a lot of people with a vested interest in Green Glue. Still don't see any evidence for it other than studies that don't even mention the product or claims made by the manufacturer or distributes, In other words, it sounds like another "Arctic Silver" to me.

We don't sell Green Glue or any similar compounds, and you'll still hear the echo from us that it works. Green Glue has independent test results in tons of different configurations (and they actually have additional tests as well that you can e-mail and ask for...though all the ones relating to isolation are posted on their website). You don't have to take our word for it -> go to their site and get the reports! These are laboratories that have to follow very strict standards to keep their certifications. I believe GG's stuff was all tested at Orfield, but they might have used other places as well.
post #34 of 53
Quote:
I'd personally like to see sound translation between 2 layers of drywall with GG versus 2 layers of the same drywall with silicone caulk, and again with latex caulk. GG's MSDS claims it's a latex polymer mixed with water, so I'm assuming its results would be very similar to latex caulk, but I'd like to see how much different.
I suggest a review of the certified third party lab test results on both the SoundproofingCompany.com website and the Green Glue website.

Whilst a "latex polymer mixed with water", like any other formulation of a polymer and water each compound will have its very own and distinct properties. Not only will latex caulk not provide the benefit of Green Glue, it will cost considerably more.
post #35 of 53
Quote:
Originally Posted by Adoniram View Post

I'd personally like to see sound translation between 2 layers of drywall with GG versus 2 layers of the same drywall with silicone caulk, and again with latex caulk. GG's MSDS claims it's a latex polymer mixed with water, so I'm assuming its results would be very similar to latex caulk, but I'd like to see how much different.

Again, statements like these just keep perpetuating the idea that GG is sort-of, kind-of, like caulk but a little better. Its just not. Just because two compounds are water based does not make them similar.

Why not smear drywall compound in between the two layers of drywall? Its a polymer mixed with water, should be pretty much the same as GG right? biggrin.gif
post #36 of 53
Quote:
Why not smear drywall compound in between the two layers of drywall?

..or peanut butter? I've heard peanut butter works just as well. Or guacamole.....that's what my drywallers called it so maybe I could have just used guacomole. It LOOKS the same so it must BE the same. I mean, right?
post #37 of 53
Quote:
Originally Posted by tlogan6797 View Post

..or peanut butter? I've heard peanut butter works just as well. Or guacamole.....that's what my drywallers called it so maybe I could have just used guacomole. It LOOKS the same so it must BE the same. I mean, right?

I still content the GG guys missed the boat by not calling the stuff "Theater Guacamole". That and a little avocado scent would have done the trick... biggrin.gif
post #38 of 53
I've tested Monoprice peanut butter and it is just as good as Monster Butter.



post #39 of 53
Thread Starter 
For those actually interested in the facts behind GG and CLD:

I took Dennis' advice and looked at all the resources on soundproofingcompany.com and one thing is readily apparent: They have put a great deal of time, thought, and effort into creating worthwhile sound-proofing concepts and materials. I have no doubt that GG is probably the best tool for the job. They explain CLD pretty much just like I did: conversion of kinetic energy into heat. This happens (as predicted earlier) by putting a layer of soft, flexible material between 2 heavy objects with high inertia (such as drywall). From an analysis point, it makes all the sense in the world that 2 layers of stiff, heavy material buffered by a soft, flexible material in between would produce excellent results.

However, there is nothing magical about GG. It's just a latex polymer. It's probably formulated to have a specific amount of elasticity, and hopefully a permanent type (some caulks harden faster than others). Again, I'm sure GG was created with this in mind. I think a lot of people here are getting confused about those of us who are simply curious about the mechanics, and instead thinking that we're trying to just find a cheaper alternative or "disprove" the facts behind GG... Some of you are even seeming to take it personally, like you made the stuff yourself, so just take it easy chaps. rolleyes.gif

Anyway, for a lot of people (myself included), a manufacturer's claims are not enough information. If that's the case for you, I bet you got a house full of broken slap-chops and shake-weights. Good for you.

For the rest of us, it's worth noting that the independent tests of GG only tested products (like drywall, studs, etc) with and without GG. There is no comparison of GG versus another latex polymer. For pure curiosity, I am just interested in seeing how it performs. That would attest to it's true value and engineering quality.
Edited by Adoniram - 4/28/13 at 10:02am
post #40 of 53
I think your thread got dragged off track due to hagbard..

We get what you are saying. There just isn't anything commercially available that is cheaper or works better. If you find something, feel free to share.

This same conversation comes up once a year or so... So when it is resurrected you get bombarded with the same answers the last person got.

Beyond it actually working, Ted White is in the forums helping people all the time... so it's not only the product that people support.. but also the people behind the product. Sometimes the support is just as important as the product. Also note he hasn't posted in your thread, which I think speaks volumes to his professionalism.

Tim
post #41 of 53
Quote:
Originally Posted by Adoniram View Post

This happens (as predicted earlier) by putting a layer of soft, flexible material between 2 heavy objects with high inertia (such as drywall). From an analysis point, it makes all the sense in the world that 2 layers of stiff, heavy material buffered by a soft, flexible material in between would produce excellent results.

Again - you are wrong. Here is one description from the FAQ:
Quote:
In a constrained layer damping system, sometimes referred to as CLD, a damping material is sandwiched between two other (usually stiff rigid) materials. For example, Green Glue sandwiched between two layers of drywall. Damping occurs when the viscoelastic center of the sandwich is sheared.

When bent, shear forces pull and stretch on the damping material. Under these conditions, the unique polymeric construction of Green Glue very efficiently converts this mechanical energy to heat. The vibration energy is not isolated, it is dissipated and gone.

So you see, the fact that Green Glue is "soft and flexible" is not relevant. (Well, it is probably a necessary but not sufficient condition). Not everything that is "soft and flexible" will behave the same.

If you want an analogy that you might be able to wrap your head around better, consider the difference between regular furniture foam, and "memory foam".
post #42 of 53
Thread Starter 
I think maybe you just don't understand the mechanics. Shear is the flexing of a material, which is exactly what I'm talking about (but maybe I'm not communicating it well). My point was that the constrained layer is the medium that is flexing with the greatest internal coefficient of friction. Stiff materials like drywall have a lower coefficient, but higher inertia. They do well to isolate some sounds due to that inertia. However, the constrained layer's high coefficient of friction due to its internal flexibility is what translates the kinetic energy of the sound wave (traveling in the drywall) into heat (non-conservative forces like friction in this case will turn kinetic energy into heat).

If GG dried as a stiff material, it would lose a great deal of its dampening quality, if not all. Flexibility is critical to its function. If you put a thick layer of sound mat up instead of GG, you'd get SOME deadening, but not as much because the sound mat doesn't have enough surface area to shear against. The flexible material needs to be in contact with the greatest surface area possible in order to translate the maximum amount of kinetic energy (sound waves) into heat. You could theoretically spray one side of a drywall sheet with rubber undercoating and achieve that result, but applying the second layer of drywall literally doubles the surface area of heat generation.

This concept is what leads me to ask how different this material is versus latex caulk. NOT to disprove anything, NOT to find a "better" or "cheaper" method, but purely for the sake of understand exactly the quality of engineering that goes into GG. If it's 10-20% better, that's awesome. If it's 0-1% better, then it's just repackaged latex caulk. I'm just curious which it is. Even if it was 0% better, I still think GG is a better buy because of its cost. But an inquiring mind wants to know how much better it really is.

I guess I just didn't explain in great enough detail? smile.gif
post #43 of 53
Quote:
Originally Posted by Adoniram View Post

...the constrained layer's high coefficient of friction due to its internal flexibility is what translates the kinetic energy of the sound wave (traveling in the drywall) into heat (non-conservative forces like friction in this case will turn kinetic energy into heat).

If GG dried as a stiff material, it would lose a great deal of its dampening quality, if not all. Flexibility is critical to its function. ...The flexible material needs to be in contact with the greatest surface area possible in order to translate the maximum amount of kinetic energy (sound waves) into heat. You could theoretically spray one side of a drywall sheet with rubber undercoating and achieve that result, but applying the second layer of drywall literally doubles the surface area of heat generation.
This is a series of logical statements that makes sense, out of context. I can't tell you what's wrong with this logic or what underlying assumption is erroneous, but I can be sure that somewhere you've got a false conception. (I don't mean that to sound confrontational, I'm not trying to argue with you.) The installation overview provided by sounproofingcompany as well as their complete installation instructions supplied with every purchase explains that the Green Glue should be applied in a random pattern, leaving gaps.
Quote:
Green Glue will compress to thin film. This film will not be continuous, and there will be desirable gaps and pockets in the coverage.

Elsewhere on this forum, Ted has warned DIYers to refrain from troweling on the GG. Again, I don't know why exactly, but there is more going on.

Perhaps there is fault in your thinking in the way you relate internal friction to flexibility. I haven't studied materials science in any way that qualifies me to speak about it, but I imagine the particular polymer structures can be a very significant factor in the degree of correlation between flexibility and internal damping potential.

Fred
post #44 of 53
Thread Starter 
The gaps probably make sense to help prevent it from moving as a single, rigid body. That's another assumption, but it seems to make sense. I can see why you'd want some shear, but don't want to make the 2 layers so well joined that they act as one.

Yes, I agree the polymer structure plays a pivotal role! I'm just curious how pivotal, and what that structure actually is.
post #45 of 53
post #46 of 53
Thread Starter 
Quote:
Originally Posted by HopefulFred View Post

http://www.google.com/patents/WO2010118359A2

Thanks! That clears it all up! You can see there was an enormous amount of testing and experimenting with different organic compounds, resins, urethanes, ceramic addition, etc etc etc... Different frequencies and damping modes were tested with all these varying parameters. Pretty cool stuff smile.gif

Here's a sample shot from that patent, comparing to Quiet Glue, which I've never heard of:
post #47 of 53
Quote:
Originally Posted by Adoniram View Post

This concept is what leads me to ask how different this material is versus latex caulk. NOT to disprove anything, NOT to find a "better" or "cheaper" method, but purely for the sake of understand exactly the quality of engineering that goes into GG. If it's 10-20% better, that's awesome. If it's 0-1% better, then it's just repackaged latex caulk. I'm just curious which it is. Even if it was 0% better, I still think GG is a better buy because of its cost. But an inquiring mind wants to know how much better it really is.

Actually, I said this before earlier in the thread - they do have a lot of tests that aren't provided on their website, including some tests that show the difference between their product and competitor's products if I'm not mistaken. I would email GG about it and ask if they have other tests. They're usually pretty quick with a response if they have anything. They may not, but it's certainly worth an inquiry as I'm sure they get asked similar questions often.
post #48 of 53
What is the typical additional cost of using green glue in a theater ?
post #49 of 53
Quote:
Originally Posted by Mfusick View Post

What is the typical additional cost of using green glue in a theater ?

budget ~$1/sq ft of drywall surface. 2 tubes recommended per 8x4' drywall sandwich at ~$16 per tube. Going with pails of GG can be cheaper.
Edited by Swervepf - 5/17/13 at 2:30pm
post #50 of 53
Yes but add some. Maybe 15%? If you're using GG, you'll also be using some extra materials elsewhere for backer boxes or soffits. Of course that's above and beyond the drywall and screws you've already committed to.
post #51 of 53
Is the purpose mainly to keep sound inside the theater ?? And not bother those outside ???

Or is it's main function to improve sound quality like treating the room with acoustic tiles and sound traps ?

I am not clear on why it's so popular. I've stopped following this forum for a few years and forgotten much of what I learned long ago. I think I know but I am trying to be clear.

Thanks in advance for insight biggrin.gif
post #52 of 53
It is used both to lower the noise floor inside the room (make it so you hear only the soundtrack / music in the room, not the ambient sounds from outside), and to reduce sound transmission from inside the room to outside. As opposed to the function of bass traps, broadband traps, diffusers, which are used to improve the character of sound within the room (keep the room from interfering with the sound coming from the speakers).
post #53 of 53
It's purpose is to stop (minimize) the transmission of sound through a wall or other laminated structure. It's a specially engineered polymer that absorbs vibrational energy (sound) and dissipates it as heat.

It is useful for those who want to shape the sound in their listening rooms in that it can help to minimize the effect of outside bothersome noises, but it is not useful in general as you would use bass traps or diffusers, or any such treatment.

Edit: simultaneous post with Brad.
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