John Sayers' Recording Studio Design Forum Archive

terrible_buddhist · Post by **terrible_buddhist** » Fri Feb 06, 2004 9:39 pm

is there an Owens Corning product @ home depot that will be similar to Rockwool? The had some R-30 there that was like 6.5 inches thick, just wondering if that would do the trick.

knightfly · Post by **knightfly** » Fri Feb 06, 2004 9:44 pm

Home Depot's vary in their stock across the country, but my local one has NOTHING that's worth taking home in insulation, other than the "pink stuff" fluffy batts which work well inside walls, but are somewhere between useless and detrimental when used as acoustic treatment inside a room. NONE of their foam products will work for ANYTHING other than heat insulation. They are all closed cell, which is a no-no.

You didn't mention what you are using the stuff for - that usually helps get more accurate answers...

Steve

terrible_buddhist · Post by **terrible_buddhist** » Sat Feb 07, 2004 1:46 am

my bad...in between the walls, between the live/dead room and the vocal booth and control room. Also need to find stuff to put into the resonators too.

I wasn't thinking the foam stuff...the R-30 said fiberglass insulation

terrible_buddhist · Post by **terrible_buddhist** » Sat Feb 07, 2004 1:51 am

actually the 6 1/4 thick stuff was R-19...check it out:

http://www.owenscorning.com/around/insu ... s/pfgi.asp

knightfly · Post by **knightfly** » Sat Feb 07, 2004 1:54 am

Inside the walls the fluffy stuff is fine, you want enough to be a slightly snug fit in the wall cavity so that it touches the panels enough to dampen them.

In a trap, I think the rigid stuff would be noticeably better if you can find it... Steve

terrible_buddhist · Post by **terrible_buddhist** » Sat Feb 07, 2004 12:10 pm

Cool I have been waiting to get Rock wool to do those walls, and it has REALLY held me up! I am going to get some of that R-19 then, does it matter if it is backed?

knightfly · Post by **knightfly** » Sat Feb 07, 2004 2:50 pm

Inside the wall, nope - (it also doesn't matter which way the backing goes, from an acoustic standpoint)

outside the wall (as acoustic treatment in the room) yup... Steve

terrible_buddhist · Post by **terrible_buddhist** » Sat Feb 07, 2004 4:33 pm

what kind of STC can I expect from using this isulation (I am doing drywall-insulation Airspace insulation-drywall) and using staggered studs. Will it improve significantly by getting rockwool?

Finally...should I use r-19 on one wall and R-13 on the other to vary the thicknesses?

knightfly · Post by **knightfly** » Sat Feb 07, 2004 5:18 pm

There is a difference of 5-8 dB between no insulation and insulation - the difference between TYPES of insulation is minimal inside walls.

You should slightly overfill wall cavities with the fluffy insulation in all cases - that improves wall panel damping.

Without a more detailed wall description, I couldn't begin to guess what STC you're looking at. There are at least 6 different thicknesses and several different types of drywall that I'm aware of, from 1/4" to 1" thick, firecode or not, greenboard for wet locations, etc - Then, you get into layers, framing methods, resilient channel, single, staggered, or double frames, etc -

If you can get more specific, so can I... Steve

terrible_buddhist · Post by **terrible_buddhist** » Sat Feb 07, 2004 7:04 pm

my question was more geared towards the insulation...so if there is little difference in STC between using R-13 and say R-30 (which is considerable more expensive) should I just get R-13 for in between the walls?

Is there any sort of method for making sure the insulation is touching the drywall?

Have you found any combinations of drywall thickness to be better than others? Say 3/8 in the tracking room but 5/8 in the control room? We are not doing RC...we are doing staggered studs. The control room floor is floated, the tracking room is not.

knightfly · Post by **knightfly** » Sat Feb 07, 2004 7:28 pm

"You should slightly overfill wall cavities with the fluffy insulation in all cases - that improves wall panel damping." -

This makes sure that the insulation touches the drywall. Where you're using the fluffy batts instead of rigid, you want as much as will snugly fit in the cavity. Less gives a little worse performance, maybe 2-3 dB.

How are you using staggered studs and floated floor? Is there a drawing already posted?

As to drywall thickness, more is always better. Different from one leaf to the other is better. Doing one leaf with 1/2, then 3/8, then 5/8 on top works well for one leaf of a wall - the other in that case should be (depending on budget and needs) either two 5/8 or add a layer of 1/2" between the two 5/8 - with staggered studs, you'll be limited to about 10 STC less than the same panel choices with separate frames, but your doors and windows will likely be the main limiting factor so no big deal... Steve

terrible_buddhist · Post by **terrible_buddhist** » Sun Feb 08, 2004 2:15 pm

I think I misunderstood stagered stud...there are 2 seperate walls, I was going to stagger the studs of those 2 walls.

knightfly · Post by **knightfly** » Mon Feb 09, 2004 2:51 am

Gotcha - normally "staggered stud" refers to common floor and ceiling plates of wider material, with staggered studs offset first to one side then the other -

fully separate frames are normally referred to as double stud. I have no official proof of this, but I believe that offsetting the studs in a double stud wall DOES help, probably by 1 or 2 STC points, due to the extra stiffness of a stud being right where the panel wants to vibrate the most... Steve

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