John Sayers' Recording Studio Design Forum Archive

Ive built a frame of 1X8 pine board and secured to the back wall behind the mix position. I intend to put in 3" mineral with about a 4" air space behind the mineral wool. (A 1X8 is about 7-1/4" deep) and then stretch fabric across the absorber for a finished look. Around here mineral wool is pretty cheap so, my question is-

Am I better off with the 3" mineral wool and a 4" airspace or should i fill the entire void with mineral wool (about 7") with no airspace?

Thanks in advance! BTW I've got pics of the absorber and slat res frames up on the wall if anyone is interested. They're pretty normal / typical / standard.

Thanks
/Jeff

Jeff - what do you mean by mineral wool - there are various versions of fibreglass, some have better acoustic properties than others.

cheers
John

http://www.thermafiber.com/PDFs/TF885.pdf

Thats the stuff. Thanks as always.

/Jeff

Greetings!

I could be wrong, but I'd think that having 3" of insulation spaced 4" away from the wall would have about the same absorbing properties of 7" or insulation filling the space. There may be a few frequencies that are the perfect wavelength to move thru it, but those could be absorbed elsewhere with 4" thick insul against the wall, so they probably won't be a problem.

Going with thinner insulation spaced away from the wall means you're buying half as much insulation. If that's not a big deal, then stuff the entire space with it.

Kase
www.minemusic.net

Kase-

Thanks. It'll be in a space where it could be easily pushed back in the opening once the fabric is installed if its bumped into. So, i guess im kinda answering my own question in saying its probably more practical here to fill the whole void simply so the stuff cant move or be pushed in. The rest of the units are slot absorbers so there is really no risk of the batts in there moving.

Anyone else have any other thoughts?

/jeff

If your absorbers are going to get bumped into, then you might want to cover them with something else to protect both the fabric and the insulation. I posted about using expanded metal sheet (like the grill over the front of guitar cabinets) as the face of an absorber earlier this week, and didn't get any negative replies. That should provide protection for the unit while letting sound thru.

Kase
www.minemusic.net

hey all,

if budget is low and you only want to buy 1/2 the insulation
You can also put a 1x1 or 1x2" frame on the inside of the 1x8" frame at the depth you want to stop the insulation so that if pushed has no where to go. Are you using rigid or fluffy insulation? If Rigid you only need the frame on the edge. The stiffness of the board will hold the middle in place unless someone is monkeying around in the room and throwing each other into walls. If fluffy is the order of the day you can just run a 2 wires (long way) across the middle attached to your inside frame.

Hope this helps.

jai
www.themixstudio.com

Thanks guys- Im usin rock wool which seems to be somewhere between rigid and fluffy. Rockwool is actually pretty cheap (and seams to be all we have around here ) SO screw it- Im gonna stuff the whole thing with rockwool and be done with it. I should be putting up fabrick and slats today!!! My fiances mom is going to sew up curtains for me hopefully in the next week or two. I cant wait to hear the room.

To all the members / owners of the site- Thanks!

/jeff

Where are ya riverside? I'm just on the other side of the river, just a block and a bridge.... There's another guy here from Milford as well.

Good luck on the room.

-bassman