Compressed cotton as sound absorber

Posted: Wed Feb 14, 2007 8:39 pm

Anyone ever work with that compressed acoustic cotton (forget exact name, assume its fairly common) and know what, if any, disadvantages it has?

Offhand I recall it having specifications somewhat similar falling bwetween Corning 703 and 705... but yet its probably 1/4 or less the price per square foot.

Is it less rigid than corning 703?
Less fire resistant?

Advantages?
Disadvantages?

I guess I'm just kind of fishing for information because I see a few web sites selling the stuff... and the specifications look pretty good, in fact if I recall, it seems to be ever so slightly better at low frequency attentuation than the Corning for a given thickness.... so I'm just kind of wondering why its not as popular?

I'm renovating the second half of my recording studio and I kind of decided that this time I want to experiment with various materials for my own knowledge and benefit... and so thought I'd check some of this cotton stuff out. It seems to come in designer colors... so I was wondering if its stiff enough, I could just make panels out of it without having to cover it with designer cloth... since it comes more or less in colors already.

I'll be buying probably another 1,500 square feet of assorted material, including Roxul mineral wool for my walls, and 705 for panels, bass traps, gobos or assorted gadgets I have to build, and I figured since this cotton stuff is so cheap.... if the specs are realy what they say they are... I could save a bit of money.

Rod?

Posted: Thu Feb 15, 2007 6:31 am

hmmmm... I wonder about how fire retardent is is. Being cotton, I would think that it should be, but probably isn't.

I might have come across this and not known it... Gotta' link?

Posted: Thu Feb 15, 2007 11:10 am

MadMax wrote:

hmmmm... I wonder about how fire retardent is is. Being cotton, I would think that it should be, but probably isn't.

I might have come across this and not known it... Gotta' link?

http://www.acousticalsurfaces.com/echo_eliminator/wall_panel.htm?d=0

It actually seems to have a slightly better nrc rating than 2 inch 3 cfs 703 Corning rigid fiber or 3cfs mineral wool, particularly at the low end; albeit slightly.

I suppose they are billing this cotton stuff as some sort of "safe alternative" or "enviromental alternative" to fiberglass or mineral wool... but in any case its supposedly around 3 times cheaper for equivelant performance and it says its class A fire rated... so it seemed like a good alternative that people could be using.

Seems like it would be best for hanging acoustic baffles. Not sure if the is stiff enough to make wall panels out of and even though it comes it some fairly nice colors, its still kind of "raw" looking and would probably require fabric covers anyway. Could also maybe use it to stuff inside of gobos instead of 705.

Posted: Thu Feb 15, 2007 1:42 pm

Is it less rigid than corning 703?
Less fire resistant?

Advantages?
Disadvantages?

Hey, my .02 is that the cotton stuff aka Bondedlogic equivelant is impressive stuff. It has some great numbers, but i've yet to see any independent lab testing of it, so you have to take it with a bit of faith. But it is an alternative product for those who like to be "green" or into the recycling factor. THey do treat them with fire resistant chemicals, like blown in cellulose products. Also, the cotton products are pretty floppy, they are primarily for between stud construction friction fit, so making panel absorbers etc will be more work than a rigid product. But making some bass corner chunks etc, would work great. Even using the large bags of cheap cellulose in your corners works very well for the price. There are many alternatives to the pricey pro-studio products, but you have to compare a couple factors...price, suitability, asthetics, performance, and of course safety. I'd use the 703/705 for certain aspects where the rigid physical nature would make it a whole lot easier to construct clouds, or wall absorbers, and use the cheaper stuff for filling cavities. Between double wall construction there is no need for anything but cheap pink insulation which performs nearly the same as most other products. Hope this helps

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