John Sayers' Recording Studio Design Forum Archive

My construction sequence has come to the point where I am almost ready to insulate the walls. (I've actually already done one wall.)

My construction is 2x4 staggered studs on a 2x6 base plate. I am using 3" rock wool in the wall cavity. The actual dimensions of a 2x6 are of course 1-1/2x5-1/2 inches. With 3" rock wool in the cavity, this leaves a 2-1/2" gap of open space inside the wall.

So, I'm wondering if it would prove beneficial to fill that void with say 2" rigid fiberglass. This would add yet another layer of dissimilar material to the wall section, and possibly provide some "dampening" of the interior wall panel.

Any thoughts?

Yeah, I'd use 3-1'2" spun glass batts with the un-faced side against the inside of the wall panels instead. This will give a slight amount of damping to each panel without affecting decoupling, and you already have enough of the heavier weight stuff in the cavities. The batts would be cheaper too... Steve

Thanks knight.
The reason I mentioned the 2" rigid is because, well, I have a LOT of it!

Here's a quick shot. It's hard to get the whole vocal booth in the shot....

Michael, if using the rigid along with the mineral wool doesn't result in tight packing, you should be fine. I'm not sure that you'll see much improvement over just the mineral wool, however. USG recommends, in their Sound Control Manual (not available offline ) that actually ATTACHING their SAFB's to one of the inner panels can be beneficial, since it changes the resonance of that side only, making the wall leaves different from each other.

Main thing is not to pack tight, or you will likely INCREASE coupling... Steve

Michael, it's hard to tell from the pix, but what is your framing and wall construction between the drum booth and the vocal booth? Also, do you ever envision cutting drums and vocals simultaneously? (Just trying to avoid possible disappointments, please get back to me on this) Steve

The wall construction between the drum room and vocal booth is simple 2x4 stud construction.

I can't imagine ever cutting vocals and drums at the same time.

Cool - in that case, never mind...