John Sayers' Recording Studio Design Forum Archive

Hi, Steve

While I think I am okay on the subjects of my wall/floor construction, I am a little confused on the "acoustic treatment" walls or slots. Is my assumption correct that these treatment walls (see my design below) are built AFTER my perimeter walls are built (including insulation, etc.) or should these acoustic treatment walls be framed at the same time as the perimeter walls....I hope my question is clear.

Would you frame for your acoustic treatment walls at the same time or is this done later? Is the double layer of sheetrock/RC/etc. still underneath the acoustic treatment walls? Assume so... Sorry for a dumb question & Happy Thanksgiving (thanks for ALL your help this year...)

Jeff

Except in the case of limited space where people use John's Inside Out walls (which won't have as good isolation due to less air space between the two leaves, but may still work fine for most people's isolation needs) -

For the most part, getting a sound proof shell is separate from treatment. The exception to this (in addition to Inside Out) would be if you had heavy masonry outer wall leaves, and wanted to have to use less trapping inside - then, a single 1/2" layer of sheet rock (or even lighter plywood, for that matter) might work for an inner leaf. The majority of the sound proofing would fall on the masonry, with the inner panel and air space doing double duty as second leaf and traps.

When building slat absorbers, you need a solid backing - this can be built as a free-standing unit and pushed up against the wall, or it could be sealed to the wall and the wall would become the back. This method would cause more loss of isolation compared to a separate backed, free-standing unit.

Also, attaching anything to your inner wall that's also attached to floor or ceiling or another wall, reduces the isolation between walls and lessens isolation somewhat. (Not as much as putting holes in the wall, though)

If your outer wall leaf isn't masonry, I would build for sound proof first - once that's done, see what the room sounds like (probably NOT pretty) - and solve the REAL problems first (is there a slap echo in here?) Does the reverb sound muddy? (too much low reverb, needs more low mid absorption) - and so on.

The "Inside out" walls need to be framed and paneled before tilting up, or you can't get to the frame to put the paneling on. That's the one thing that makes them difficult.

And yeah, the acoustic treatment needs to be INSIDE the inner sound proofing leaf, or it's not much acoustic treatment (It's mostly what surface is presented to the sound field that makes the acoustics what they are)

Hope that helped - You're welcome, and a Happy Thanksgiving to you and yours as well... Steve