John Sayers' Recording Studio Design Forum Archive

hi....me again!

with an update on our studio construction.....

we built 2 slot absorbers (to spec w/ rockwool inside), came out great!

but, we have to build many more, so i was thinking about another SHORTCUT (u know me & my shotcuts! )

just feel free to tell me im stupid and why it wont work or whatever....but i could save a few bucks if i:

use 2 x4s instead of MDF for the rear wall absorber panels (no slot front)that would mean 2 inch width instead of 8 inches. i would stuff the 2x4 & plywood frame with rockwool, so there would be no space. do i need the space?

also, i know that the slot absorbers & corner absorbers need to be sealed. but, is it absolutely necessary that the rear wall absorber panels are sealed?

thanks again!

blackdrum

Depth for the rear absorber helps, the further off the wall your absorbent the deeper the frequencies affected. Sealing isn't necessary here, it works by the sound "squirming its way through the fibers", hitting the wall, and "squirming its way back" again - boy, was that tiring...

If you stand your rear absorbers off the wall, make sure the back of the absorbent is open or you're wasting that space for nothing... Steve

when you say "back of absorbant" do you mean the insulation itself?

so will the 2x4s work in place of the MDF?

thanks again!

i have lots of pics of before & after which i will post soon!

I'm no expert (not by a long shot) but I think the 6 inches of difference will cause the absorber panel to be much less effective.

anybody else?

If you're just building a broadband absorber, then your material IS the absorber. The further you move it away from the wall, the lower frequencies it will affect. For this type of treatment since any air space between wall and absorber actually HELPS even out absorption, you do NOT want a back on the absorbent material (the insulation, whatever kind you're using, the rigid board kind works multiple times better than the "fluffy stuff" - for this type of treatment, the only thing the frame is there for is to hold the absorbent material in place and to look good. If your absorbent material is stiff enough, and you don't care what it looks like, then you can just wrap it in burlap or something that will keep the fibers from being a problem. Keep in mind that most cloth is flammable - some of the expensive stuff is NOT flammable; you can also get spray-on treatments that will improve regular cloth, here's one source -

http://www.natfire.com/

Hope that helped... Steve

thanks sooo much for clarifying that...i was under the impression that the absorbers had a plywood back (and i was wrong!)

i have all the wood & mdf cut, and i am about to start putting these things together. i bought a case of acoustic sealant (may have alot left over if anyones interested !) i chose to go w/ rigid fiberglass because its less messsy.

it seems like my control room is going to be very small when im finished...but at least my mixes will sound good!

should be finished in a few days. ill post some pics!

thanks again!

Blackdrum