Room treatment material
 

Seems everyone recommends Owens Corning 703 for homemade standalone noise catchers. I have an extra mattress topper of "high density memory foam." 77×76, 3" thick. Cut up and mounted in wood frames, would this stuff work "pretty well" ? I figure "low density" would be better (bigger holes.) Nevertheless, worth the construction effort?
Thanks.

No idea, but if you're going to make the effort, why would you not go with what is known to work best?

It takes *mass* to treat low frequencies, which is the main reason compressed fiberglass or rockwool are the preferred materials. Whether your foam will work for you depends on what you are recording, and mixing if it's meant to be treatment for a mixing space using monitor speakers.

Memory foam is quite heavy but, I suspect, insufficiently porous to be an effective absorber. It might work ok as a limp mass but why bother, it's much simpler to use the acknowledged 'best' materials for the job. The other issue with memory foam is the construction of the frames, RW3/703 is sufficiently rigid to be self supporting making the frames much simpler to construct. The optimum density mineral wool for ease of use and best absorption is around 60 kg/m3. My frames are extremely simple, just a perimeter of 2' x 1' PAR softwood butt jointed with a couple of screws in each corner, inside dimensions a fraction under sized so a 1200 x 600 mm mineral wool panel stays put inside. cover with suitable fabric and hang em on the wall/ceiling. Happy to post a diagram if it might help.

"Work pretty well" is kinda subjective. But it does work to some extent, to tame some high frequency zing is about all it does.
Even thought it has been highly promoted as room treatment. IMO foam is the least desirable kind of wide band treatment. And no low density foam will not work better, probably work less well
As others have noted if you're going to the trouble to build wood frames why not just get some Corning 703 , or Roxul Safe and Sound

What are you hoping to do with your sound treatment? Control the acoustics of the room or isolate it from the outside world?

Bob

No, you want high density. 'Holes' let the sound go through (and then bounce off whatever is behind them)..

Because I already have the material, have never used it for anything, and it is made out of petroleum. I enjoy repurposing products having relatively high carbon footprint, or are not nice to landfills.

To control acoustics for just solo NS guitar recording.

But even the high-density stuff allows sound waves to pass through. That's what attenuates them. So you need "holes" of a sort. If the sound waves don't go through at all, they are reflected, which is exactly the problem we are trying to prevent.

My guess is that memory foam isn't sufficiently "porous" to attenuate the sound energy like you want. It may absorb some but not nearly as well as the standard panel materials.

No, what attenuates the sound is absorption by the material, which actually converts it to heat. More/larger 'holes' (greater porosity) lets the sound waves go through with less absorption.

OP:

Foam is a very different substance than fiberglass insulation. There is no comparison.

Use the memory foam to sleep on and use an appropriate material for sound control.

Ok, that seems to be the consensus. Thanks everyone!