Best wall sandwich?

  • Thread starter Thread starter laptoppop
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laptoppop

Musical Technogeek
Has anyone done any testing of triple layer wallboard (varying thicknesses, of course) versus a wallboard/plywood/wallboard sandwich? (not MDF, plywood)

I did my home studio in a wallboard/plywood/wallboard sandwich and it turned out GREAT. I can put a screw in any wall anywhere and hit wood. The sound isolation from outside is also very solid. I'm wondering if the different layers, with different resonant frequencies, etc. actually work better than the same amount of mass would be if it were all wallboard. I also wonder if plywood with its internal layers would work better than MDF.

Anyone have actual data?

Thanks,
-lee-
 
Lee, I too haven't seen any lab tested walls using plywood in a sandwich - however, there's not a lot of difference in mass between plywood and a slightly thinner center gypboard layer - so STC should be at least as good, as long as you don't put fasteners thru the sandwich where studs are located. That would flank through the stud and to the other side of the wall, where if you penetrate just into the stud cavity, insulation will pretty much kill any minor sound that leaks into the cavity. And, since your screws to fasten things to the wall would only need to be long enough to penetrate the plywood, you wouldn't even need to penetrate into the cavity.

The advantage of being able to hang stuff on the wall would be a fair trade for a couple dB difference, and I'm not even sure you'd lose that much. The layering of the plywood, with the glue lines between layers, and the (very) different speed of sound betwen gypsum and wood could easily BEAT using a thinner center gypboard layer.

Bottom line is, if it works well enough for you, who cares what a lab report says? "If a tree falls in the forest..." Steve
 
No test data exists that I am aware of.

Mostr probably because the manufacturers of plywood and MDF don't see a large enough sales base for using their product in this manner to justify the costs of testing.

X- Rated drywall on the other hand - seeing as their product also provided increased fire seperation (and none of the wood boards can provide this) can burn tons of money on this.

Interesting that the study Ethan refered to - which has 350 seperate cases they dealt with - did not address either this issue - or the concept of varying thicknesses (in a multiple sheet installation). Just standard installations with the same thickness on all of the wall surfaces.

Bottom line is what Steve said - if it worked for you - then in the end that is all that matters.

However - I would have a hard time reccomending to anyone that they spend their money on anything that i could not provide them test data on.

I would hate to have someone actually have an acoustical engineer provide some testing on their environment and then have them screaming at me bacause they spent "X" dollars extra for "Y" improvement on their wall just to find out that it didn't really work after all.

I hope everyone has a simply magnificent holiday.

Rod
 
Thanks guys. Yah, it worked for me on my little one-room studio. However, I'm considering building a bigger facility, and may use the same technique in it.

-lee-
 
Well I did the wall between the control room and live room with triple layers of Wallboard. What I can say is what little Low end was creeping through room from the CR side was eliminated. PERIOD!!!

It was amazing to see how much low end was being trapped between walls, especially when I cut my window opening on the Live room side.

I Had people, before I cut the opening bangin on the walls Hard and Never heard a thing.

Bryan Giles
 
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