Now this will be interesting if and when it comes out

[pratul]

Would have been great if this was available when I built my theater. If it works like they claim, it will help a lot.

New Spring-Loaded Screw Turns Drywall Into Sound-Absorbing Panels

"Sound Screws" might one day be an easy way to tune out noisy neighbors.

gizmodo.com

 

[Travis Ballstadt]

Very interesting.

 

[FargateOne]

indeed...

 

[Sonnie Parker]

Hmmm... would be interesting to see their testing on this.

I have 3/4" plywood, then 5/8" rock on top of that, with green glue in between, so not sure if they would help in my room.

 

[Travis Ballstadt]

Hmmm... would be interesting to see their testing on this.

I have 3/4" plywood, then 5/8" rock on top of that, with green glue in between, so not sure if they would help in my room.

Hard to tell based on the limited info/photos, but I'm assuming they would need to produce different pieces for 1/2 vs 5/8 materials, and load-testing data would tell if it could handle the weight of the multi-layer green glue technique.

I haven't researched it in awhile, but what is the data on the decrease in transmission with dual-layer drywall with a green glue layer? How does that compare to the (I think it said) 9db that these screws offer?

 

[Sonnie Parker]

Hard to tell based on the limited info/photos, but I'm assuming they would need to produce different pieces for 1/2 vs 5/8 materials, and load-testing data would tell if it could handle the weight of the multi-layer green glue technique.

I haven't researched it in awhile, but what is the data on the decrease in transmission with dual-layer drywall with a green glue layer? How does that compare to the (I think it said) 9db that these screws offer?

Not really sure... but I don't have dual layer drywall... it's 3/4" plywood, on staggered studs, then green glue and drywall.

Well... actually I do have dual layer drywall, on the outside wall facing the house. I did two sheets of 5/8" there instead of plywood underneath on that side.

 

[Travis Ballstadt]

Just curious what the difference between the most common dual layer green glue setup and these screws would be. Seems like it could be a VERY cost-effective and less hassle alternative for those who may or may not need complete isolation. Like, if these were available today and I was building a new house, or even a new theater, it would be a no brainer to use them on every sheet of drywall, theater or not.

 

[Sonnie Parker]

I'm not sure if green glue has every been tested... or maybe it has and I've not paid any attention to it. I used it instead of silicone, as I wanted some sort of sealant between the sheets, and figured why not use green glue if it might help.

 

[Travis Ballstadt]

I'm not sure if green glue has every been tested... or maybe it has and I've not paid any attention to it. I used it instead of silicone, as I wanted some sort of sealant between the sheets, and figured why not use green glue if it might help.

Oh it's been tested. Here's a whole slew of tests, if you can find something similar to your build.

Where to Buy

Find a local distributor or an online retailer of Green Glue Noiseproofing Products, many online retailers can also help answer Green Glue Soundproofing questions.

www.greengluecompany.com

 

[MediumRare]

Those screws MIGHT absorb higher frequency vibrations, but then enable lower frequency ones, not only in transmission but in resonance. Test data would be essential.

 

[MediumRare]

Oh it's been tested. Here's a whole slew of tests, if you can find something similar to your build.

Where to Buy

Find a local distributor or an online retailer of Green Glue Noiseproofing Products, many online retailers can also help answer Green Glue Soundproofing questions.

www.greengluecompany.com

Could you explain how to interpret these tests?

 

[Travis Ballstadt]

Could you explain how to interpret these tests?

I actually can't. I'm sure there are much smarter folks on here than me who could help out, though. Perhaps @Matthew J Poes would be best to interpret.

 

[pratul]

Yes, the screws are interesting if they perform as well as they claim. Mainly for new constructions. Let's see if they even go into production.

 

[pratul]

Not really sure... but I don't have dual layer drywall... it's 3/4" plywood, on staggered studs, then green glue and drywall.

Well... actually I do have dual layer drywall, on the outside wall facing the house. I did two sheets of 5/8" there instead of plywood underneath on that side.

I wish I had done something similar when we built ours. Our theater has nothing special to isolate it from the rest of the house. My wife goes out for a "drive" whenever I am listening to music . Our theater is in the basement and it is loud even on the second floor. I do have fiber glass insulation between the studs on all the walls and between the ceiling joists but they don't do squat.

 

[Sonnie Parker]

I had half the garage as an HT room... tore it out and went back to a full garage because as I told her, it was just too small for me. I put the HT back in the great room, which is between the kitchen and our bedroom, so she got a good dose of bass all the time. It wasn't long before she gave me the okay to take the entire garage, and I told her I even make a hallway between the house and the room to help insulate it.

Tearing out the first one and putting the HT back in the great room was a BRILLIANT plan.

 

[pratul]

I had half the garage as an HT room... tore it out and went back to a full garage because as I told her, it was just too small for me. I put the HT back in the great room, which is between the kitchen and our bedroom, so she got a good dose of bass all the time. It wasn't long before she gave me the okay to take the entire garage, and I told her I even make a hallway between the house and the room to help insulate it.

Tearing out the first one and putting the HT back in the great room was a BRILLIANT plan.

LOL that was an awesome but sneaky plan Hope she doesn't read these forums

 

[BenToronto]

About walls, it is complicated. The Gizmoto article is almost total acoustic gibberish.

Basically, there are two faces to sound control here: transmitting through walls and absorbing it in rooms. The paneling can influence both.

Ordinarily ordinary drywall absorbs some bass. Perhaps making the panels springy makes them tuned and absorb more.

And drywall - unless resiliently mounted - transmits sound pretty well (in both directions). Many ways to decouple drywall from the wall behind but hard to see a little spring in a screw do the job.

The answer is: Tectum. Looks like shredded wheat made from wood. With some acoustic fibreglass behind, Tectum panels is one of the few treatments that absorbs any bass.

B.

 

[Sonnie Parker]

LOL that was an awesome but sneaky plan Hope she doesn't read these forums

Ehhh... she figured it out.

The good thing is she can't hear a thing... pretty much. If I watch a really bass heavy movie she can sometimes hear what sounds like distant thunder, but that don't bother her because it is faint. Having layered 8-9" thick walls and the hallway between the room and house, really helps.

 

[Matthew J Poes]

I actually can't. I'm sure there are much smarter folks on here than me who could help out, though. Perhaps @Matthew J Poes would be best to interpret.

I can explain the tests. Basically they test a wall assembly (meaning a mock-up of a wall) to see how much sound passes through it compared to no wall. The difference is the sound transmission loss. This is compared against a standard curve known as the sound transmission curve. This then gives it the rating.

of course it’s not all that useful if you don’t know what a reference wall would be. As such, it is standard practice to also test a regular untreated wall as a point of comparison.

and that is where the rub is. A lot of products don’t perform so well once the reference wall is compared on equal grounds and margins of error included.

the actual margin of error on a TL test is a lot higher than the standard error reported. Evidence of that comes from the variance in inter-lab studies.

having said all that. Green glue has been extensively tested. It works. It isn’t as good as I would like it to be. But it does work. On a 24” OC wood or steel stud wall, it adds a small amount of useful decoupling and a large amount of damping. As the wall design inherits more and more decoupling through different construction, and wall mass goes up, the decoupling value of green glue becomes null. Further, it’s damping becomes less apparent.

what that means is that in really serious soundproof assemblies you have to weigh the cost benefit of using a product like that. It may not add much if any benefit. In a steel double stud wall with insulation in the cavity and 4 layers of drywall, green glue offers no benefit over a reference wall in terms of STC. It does offer some damping of resonances which is still helpful.

these screws would be no different. In more serious assemblies, they likely wouldn’t do anything. These are for very low level assemblies where you want better than nothing.

I am currently building a new house in Florida and I am doing a new product for decoupling that uses two plates of plywood with a silicone isolator. Silicone acts as a inherently damped spring. Metal springs have much less self-damping. The partition walls in my new room will be double stud. This involves two stud walls back to back. They are physically separated from each other. As such the room itself is inside the house, not a part of it.This room is then only couples to the rest of the house via silicone springs. That ensures very little energy can transfer from inside the media room out (or outside in).

 

[BenToronto]

Truly excellent report and superior writing too. Thanks.

Very ambitious plan you have for FL. Must be exceedingly difficult to ensure total floating. As with little holes that let a lot sound slip through, even a bit of contact would be damaging.

I suspect it is helpful for sound quality to have rooms that are kind of resilient and porous, rather than solid and hence, resonant. But for isolation, some conflicting issues.

 

[Matthew J Poes]

Truly excellent report and superior writing too. Thanks.

Very ambitious plan you have for FL. Must be exceedingly difficult to ensure total floating. As with little holes that let a lot sound slip through, even a bit of contact would be damaging.

I suspect it is helpful for sound quality to have rooms that are kind of resilient and porous, rather than solid and hence, resonant. But for isolation, some conflicting issues.

Thanks!

it probably is ambitious but it was important for me. It’s not too bad to create a floating floor. Plywood isn’t a rigid plate. It can bend. That means that even if the edges were rigidly mounted (which they are not), you still get benefit from the bending. In this case, the walls are all decoupled. The floor inside the room is 1/4” smaller than the stud wall boundary. It doesn’t touch anything that is rigidly mounted. The plywood sits on top of these spring mounts. Insulation sits between the sprint mounts to fill the 2” airgap that is formed by this. The result is a floor that totally floats.

of course nothing is totally soundproof and sound energy will still get through. But this is much better than usual. A typical wood floor might have an STC and IIC in the 30’s at best. Maybe low 40’s if the flooring is LVP or a good isolation pad is used. Not all that great. This floor will be between 15 and 20 points higher.

as for the needs of isolation and sound quality, you are right to a point. It’s a balancing act to be sure. A lot of people misunderstand soubdproofing and assume big massive walls are best. That isn’t really true. The decoupling is actually the single most important factor in sound mitigation. Not mass. Mass matters, but breaking the energy connection between the inside and outside of the wall structure makes a far bigger difference. That is also good for sound. It allows the wall to dissipate a large amount of sound energy. It slightly lowers the walls acoustical impedance reducing the propensity for a reflection at low frequencies.

however mass and stiffness are still a part of the equation and these are both bad for sound quality. High mass is still needed to stop more sound. So while decoupling is the first priority, once it’s decoupled, yoI do need to ensure there is sufficient mass. This raises the amount of energy necessary to move the structure. Thus less sound can pass through. But adding mass usually adds stiffness.A room is a pressure vessel at low frequencies so that contains more of the LF sound as stiffness increases. That’s not a bad thing for sound isolation but it does cause modes to be much worse. In fact all LF reflections are worse. The energy in a Lf wave is so great that the resilience and damping of the wall becomes inconsequential. You just couldn’t make it floppy or damped enough to dissipate all that energy without having a ridiculous and probably illegal room. That all becomes a problem that needs to be balanced.

what I try to do is create sandwich walls that utilize high amounts of decoupling, large air gaps, and many dissimilar materials throughout to get as much TL without raising the stiffness too much on the inner shell. This new room will use 2 layers of drywall. It’s needed. But I am using 2 layers of plywood on the outer shell of the exterior walls. inside the wall has a layer of high density foam board insulation adhered to the purser shell and then R38 insulation. Then Decoupling, followed by the two layers of drywall. I’ve decided not to bother with GG this time. The benefit is likely to be little or even nothing at all. But expense would be high, especially the added labor costs.

 

[BenToronto]

Sounds highly intelligent and was very educational for me. Thanks. Fun daydreaming about how you might do doors and windows, water pipes, electric outlets, lights.....

Any value to my favourite Tectum, perhaps substituting for dense fibreglass panels? One of the few panels with any bass absorption and architectural use.

Meaning of your allusion about "illegal"... esp in ill-regulated Florida?

Interesting about your room being a pressure vessel. Tons mis-spoken about bass enhancement - which can only be accomplished in seriously sealed cars and not in ordinary rooms with drywall, doors, and windows. So it is possible you may have the goose with the golden eggs and free bass boost.

B.

 

[Matthew J Poes]

Sounds highly intelligent and was very educational for me. Thanks. Fun daydreaming about how you might do doors and windows, water pipes, electric outlets, lights.....

Any value to my favourite Tectum, perhaps substituting for dense fibreglass panels? One of the few panels with any bass absorption and architectural use.

Meaning of your allusion about "illegal"... esp in ill-regulated Florida?

Interesting about your room being a pressure vessel. Tons mis-spoken about bass enhancement - which can only be accomplished in seriously sealed cars and not in ordinary rooms with drywall, doors, and windows. So it is possible you may have the goose with the golden eggs and free bass boost.

B.

All rooms will act as a pressure vessel at some point. Very tight rooms like basement theaters a pretty well sealed. Especially those with soubdproofing.

cars are small. That’s all. Their volume causes the pressure vessel effect to start higher up in frequency. They are stiffer too of course which helps. A room doesn’t act as a pressure vessel until something like 30-40hz. Really large rooms would be even lower.

Florida still follows the same fire standards of most states. As such, a wall has to be made of a solid material. You couldn’t have a room pass code made of just MLV or some other soft material.

 

[BenToronto]

Thanks for good reply. In addition to the substance of walls, fire control regs insert solid fire breaks between the studs in some places so flames and smoke can't climb up. Ummm, now that could be another challenge to isolation. Or in Florida, strongly attached roofs due to hurricane risk.

Without disputing your faith in pressure vessels, I know you wouldn't want readers to have unfulfilled faith that a boost, should any be found, is more than a dribble of db's at the best, assuming the drywall panels are real stiff.

B.

 

[Matthew J Poes]

Thanks for good reply. In addition to the substance of walls, fire control regs insert solid fire breaks between the studs in some places so flames and smoke can't climb up. Ummm, now that could be another challenge to isolation. Or in Florida, strongly attached roofs due to hurricane risk.

Without disputing your faith in pressure vessels, I know you wouldn't want readers to have unfulfilled faith that a boost, should any be found, is more than a dribble of db's at the best, assuming the drywall panels are real stiff.

B.

Ben I think you underestimate roomgain. We have done a lot of testing of subwoofers outside both here and at Audioholics. James Larson and I combined have tested likely 100+ different home subwoofers outside. We sweep them and test max output. I have also had a pair of contracts to test speaker maximum output and develop a meeting standard for closed loop speakers. In that testing I needed to identify the problems of testing maximum output in-situ by quantifying the difference.

when you address the effector modes and such, which is no easy task, all rooms will exhibit gain. It’s not trivial. It’s not a db or two. In fact at low frequencies it approach 20+ dB. Simply measuring a full range speaker inside vs outside at the same voltage can realize 3-6 dB of gain.

may very low frequencies the amount of gain depends on how closed up the room is. You sometimes see as much as 10dB more bass below 20hz just by closing a door. This was all stuff I had to figure out to make sure my protocol established clear criteria under which it was possible to measure a speaker inside and give accurate maximum output data.

cars are certainly a lot higher and that gain starts rising earlier. Basically the entire sub range is boosted. That isn’t true in a home as much.

my guess for the myth of no room gain is that modes really mess that up and the response od a speaker often still falls off a cliff when you get deep enough. But that is because with many subwoofers the output drops well below the noise floor.

this is a measurement comparison using two methods of capturing the data that Does a better job when noise is very high.

this shows the room gain and true in-room response.

a sweep method that had an overly short sweep and FFT length, too low volume for the noise, and this shows this sharp rolloff that isn’t there.

the sub in question has a free space -3dB point of 30hz. It’s -10dB at 20hz. It’s a push pull sealed design. We are seeing about 20dB of room gain based on the results here.