I have some large panels I want to build (around 4' by 8' with an arched top) and in these panels, I want to place some OC703 - 2" thick and as much surface area as I need for room acoustics.

I want to build these large panels separate from the wall and attach them after they are built (in a fashion that I could take them down, if need be). I'm brainstorming how to build these and was thinking of making a big wood frame (2" deep) that outlines the whole panel. For the back of the panel, I was thinking of using wire fencing (14ga wire with 2" by 4" openings) attached to the wood frame. I'd then put in a small layer of cotton batting and place the OC703 on the batting where I want it and some other non-absorbing solid material (maybe styrofoam) to fill the remainder.

On top of that, I'm thinking of putting another layer of wire fencing so the insulation is sandwiched inside the fencing. To finish off the panel, some cotton batting over the front wire fencing and cover with fabric (GOM).

The biggest question I have about this is whether the wire fencing will have any effect of the performance of the OC703 as a sound absorber and if it does, is that effect significant enough that you wouldn't want to do it?

Also, if it doesn't have much of an effect, how about using wire fencing with smaller holes? I'd really like the fabric covered panels to have a little protection if someone pushes on the outside and I am thinking this wire fencing might be a good thing to use to hold the insulation in place.

That's a pretty big panel. What are you attempting to use this for? depending on what it's for, treatment above ear level may be unnecessary. If you really need that size, consider a ladder-type frame for stability. There are a dozen ways to account for easy removal; velcro, speaker grill grommets, hidden screws, etc.

From the posts I've read here, 2" thick might be an inch too much for your panels. A lot of folks use 1" Linacoustic or similar to construct theirs. The fencing sounds unnecessary to me. I can understand the need to prevent damage, but (again from what I've read) properly stretched GOM and duct liner are pretty resilient.

Your cotton batting idea sounds like it might defeat the acoustic purpose of the insulation underneath, since the cotton is more reflective than the insulation. Plus, it sounds like you're only suggesting it to keep the fencing from poking the GOM.

Have you read the acoustical treatments master thread? A lot of great insight there. I'd do a search on Linacoustic to see what others are up to as well.

Have you looked at Greg Power's thread:

http://www.avsforum.com/avs-vb/showthread.php?t=487747

Also Steve Withey is plotting a new novel approach, but its in skunkworks still, so you'll have to wait a few days:

http://www.avsforum.com/avs-vb/showthread.php?p=11678027#post11678027

Thanks. I'm mainly concerned with what putting wire fencing in front of the insulation does.

For the front, if small holes in the wire fencing are acceptable, I could use a small wire mesh fencing (chicken wire) with a higher gauge wire for the front.

I just think wire fencing to sandwich the insulation in would add a lot of stability to the panel.

How small could the holes in the fencing be before sound absorption by the insulation behind it is affected?

I know I've seen some DIY bass traps built by sandwiching insulation between wire fencing and rolling it into a cylinder. This type of bass trap is supposed to be very effective.

So, I'm thinking most sound will pass right through a wire mesh fence or at worst be diffused.

Why not use 705 which is more rigid, space it off the wall 1 inch or so, you can even use the 705 material as a 4 inch border to space it off and wrap fabric.

My biggest question is whether wire facing the insulation will defeat the purpose of the insulation. I know that if I stand on the other side of a fence or even a screened door, I don't think the sound that passing through the fence or screened door is much affected, but I'm no expert.

In fact, it might be nice to face the panel with a storm window screen (very small holes) as that would give a real good feel if someone pressed against the panel. If it were stretched like in a window, it would also give some rigidity to the panel.

But, I just don't know when a wire screen goes from being basically AT to being reflective. Anyone know the answer to this question?

Just found this insect screen that is made of fiberglass...

http://www.qualitywindowscreen.com/store/index.php?main_page=product_info&cPath=65_114&products_id=185

Maybe something like this would be good to sandwich the insulation for the panel?

And if I want to face this wire screen with a thin layer of quilt batting to soften the feel of the panel between the GOM and the insect screen, what material should the batting be made of? Polyester, cotton, or a blend?

I'm thinking such a layer would be so thin that it really doesn't matter much. No panel is going to be 100% absorbent and I don't think small amounts of reflection due to this screen or batting or the cotton GOM is going to make much difference in the performance of the panel overall.

But, maybe I'm wrong about this. I don't want to go overboard by trying to build an aesthetically pleasing panel only to defeat the whole purpose of the panel in the first place.