Soundproofing a room - decoupling, green glue, etc.

David Matz · Apr 29, 2010

Green glue seems to be the "consensus best" product for sound proofing based on my research. Anyone here put it in? How do you like it?

How well does it work for bass frequencies? I imagine it would be hard to get rid of that thump-thump, even if the rest of the frequency range has been killed off.

Anyone here de-couple the studs in the walls to minimize the sound vibrations?

I imagine doing both is the best way to go.

Thanks!

JonFo · May 1, 2010

David Matz said:
Green glue seems to be the "consensus best" product for sound proofing based on my research. Anyone here put it in? How do you like it?

How well does it work for bass frequencies? I imagine it would be hard to get rid of that thump-thump, even if the rest of the frequency range has been killed off.

Anyone here de-couple the studs in the walls to minimize the sound vibrations?

I imagine doing both is the best way to go.

Thanks!

David, yes, doing both is what you'd need to do to get rid of room-to-room transmission.

But I've found that unless you do the total room-within-a-room thing, it's pretty hopeless (or your subs not very good

)

I've never used the green glue, but have read it really works.

DrJRapp · May 1, 2010

Decoupling and trick glues are useful in new construction and where space allows, however in a retrofit I find that two staggered layers of Quietrock does the trick on all but the lowest frequencies.

RichTeer · May 1, 2010

DrJRapp said:
Decoupling and trick glues are useful in new construction and where space allows, however in a retrofit I find that two staggered layers of Quietrock does the trick on all but the lowest frequencies.

My understanding is that in situations like that, Green Glue would be used between the two layers of Quietrock.

DrJRapp · May 1, 2010

RichTeer said:
My understanding is that in situations like that, Green Glue would be used between the two layers of Quietrock.

Not necessary. The effects of layers of differring sound control material are not cumulative. Quietrock works by disipating the sound energy within itself, not by decoupeling. The difference between using green glue between layers vs regular drywall mud (as a laminating adhesive) is about 2%...and the cost difference is huge.

Bernard · May 1, 2010

DrJRapp said:
in a retrofit I find that two staggered layers of Quietrock does the trick on all but the lowest frequencies.

Is that what you call "Jerry-rigged"?

Sorry, could not help myself :devil:

That expression is very frequently incorrectly used as "jury-rigged"; bugs me when I see that.

Ted White · May 3, 2010

DrJRapp said:
Not necessary. The effects of layers of differring sound control material are not cumulative. Quietrock works by disipating the sound energy within itself, not by decoupeling. The difference between using green glue between layers vs regular drywall mud (as a laminating adhesive) is about 2%...and the cost difference is huge.

That is not so.

Scenario #1 is simply adding mass to a system by applying drywall compound between layers of drywall. Heavier walls result, but not damped.

Scenario #2 is adding a damping compound between layers of mass for the purpose of damping that mass.

The effects / results oif simply adding mass vs. damped mass is well known and documented. Also, factory damped drywall is nothing more than standard drywall or cement board with a damping compound in between.

DrJRapp · May 3, 2010

Ted White said:
That is not so.

Scenario #1 is simply adding mass to a system by applying drywall compound between layers of drywall. Heavier walls result, but not damped.

Scenario #2 is adding a damping compound between layers of mass for the purpose of damping that mass.

The effects / results oif simply adding mass vs. damped mass is well known and documented. Also, factory damped drywall is nothing more than standard drywall or cement board with a damping compound in between.

I sugesst you go read the data on Quietrock. Then go study the physics that go into NC criterion. Study the STC tests for quietrock, and the STC tests for green glue (whoops there arn't any for green glue).

RUR · May 3, 2010

FWIW...

Ted White has had a long interest in science, receiving a Bachelor’s Degree with dual majors in Biology and Chemistry with a minor in Physics from The State University of New York. A twist of fate led him to start a career in Building Materials in 1983. He has been working with Builders and Architects for 26 years now.

Ted started building a home theater back in 1998. The lack of proper sound isolating materials and techniques led Ted to start supplying soundproofing materials to others. This interest in high performance soundproofing eventually led Ted to his involvement with establishing the Green Glue Company in 2004. Green Glue quickly became synonymous with high performance and low cost soundproofing.

Identifying that the market needed a commercially oriented distribution channel that offered a comprehensive product assortment, simple straight advice while delivering low cost materials, Ted formed the Soundproofing Company with John Hile. Although they sell many products, the Soundproofing Company became the world’s largest distributor of Green Glue in 2008.

http://www.soundproofingcompany.com/company/

DrJRapp · May 3, 2010

I thought I smelled advertising.

Ted White · May 3, 2010

I'd agree with the "advertising" comment if I were promoting a product. I am not. I also didn't introduce any link.

I'm quite familiar with the topic at hand. Quiet Rock, Supress, Comfort Guard and SoundBreak are all examples of factory damped drywall. Standard drywall or drywall/cement board with a damping layer in between. My point being you seemed to dismiss damping materials as "trick glues" when in fact the drywall you recommended uses this technology.

Most of the products mentioned in this thread have been thoroughly tested for most of the last decade.

DrJRapp · May 3, 2010

Ted White said:
My point being you seemed to dismiss damping materials as "trick glues" when in fact the drywall you recommended uses this technology.

Most of the products mentioned in this thread have been thoroughly tested for most of the last decade.

I'll need to review your data

Ted White · May 3, 2010

Both systems employ Constrained Layer Damping (CLD). Both use two layers of mass, with a visco-elastic material applied in between. The panels flex, creating a shear force on the damping layer, which creates friction. This is the energy conversion to heat.

Have you looked on their website for data? I would agree that products with no data can't be taken seriously. Agree 100%.

DrJRapp · May 3, 2010

I had a chance to quickly review the data and it appears that when applied properly in a given wall assembly that green glue can reduce sound transmission in the 500-3k hz band about 5 db...which is nothing to sneeze at. I may actually give the stuff a try in my next project that requires a wood floor be isolated from the concrete slab below.

Ted White · May 3, 2010

I think you'll find that a damped system will increase TL from the fundamental LF resonance point all the way up to the coincidnce point. This can be seen on anyones TL plot.

You made the #1 biggest point of all. "If properly installed." Like anything else there are optimal conditions and also much less optimal conditions. CLD systems don't always work for all isolation applications.

Take your floor example for a moment. This is a good example where a damping material would not be best. The slab and the wood floor have too great a difference in their stiffness. No effective damping of a slab can occur. It's intuitive that a damping layer between the wood and the slab might do something nice, but this is not the case.

RUR · May 3, 2010

A pity this expertise wasn't around when I built my dedicated audio room 17 years ago. At that time, the only source of information on room sound-proofing I could find was in the woodworking community e.g. articles in Fine Woodworking and the like. At that time, the "preferred method" was stuffing the studs with Thermafiber and hanging the drywall on J-channel. Yes, it's a decent improvement, but certainly not on par with what can be accomplished today.

David Matz · May 3, 2010

Gentlemen,

Thanks for the replies. I believe the Soundproofing company is a legit operation. Ethan Winer recommends it on his site, and I don't see him recommending shysters.

As for my project, I am interested in controlling the bass as much as possible so my wife doesn't complain about the thump-thump. This seems like a green glue solution rather than Quiet Rock. I don't have the space for double studs, but I have a some space for double dry wall with Green glue. I also possibly have some space for clips that can be used to attach a metal bar to decouple the walls. This will depend on how much space in the room I will lose because of that. I will stuff the wall with r13 insulation for further absorption.

Ted White · May 3, 2010

You could modify single stud wall to staggered. Save on the clips. Takes up 1" of space and offers good decoupling.

David Matz · May 3, 2010

Ted White said:
You could modify single stud wall to staggered. Save on the clips. Takes up 1" of space and offers good decoupling.

Thanks, Ted. How does the single stud staggering work and how much space do I leave between the studs? Is there a picture anywhere?

Thanks

Ted White · May 3, 2010

David. Have a look at this link. http://www.soundproofingcompany.com/library/articles/staggered_stud_wall_construction/

If posting links like this is frowned upon someone please let me know. Its a generic article.

Soundproofing a room - decoupling, green glue, etc.

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