Foam. Completely worthless?

[allbaldo]

I mix at home in a far less than ideal room, and I'm trying to do some DIY treatments to improve things. I have almost no $ to spend toward this goal, but I do have a few things laying around. I have four 4" rockwool sheets which I'm using to make four 2ft x 4ft broadband absorbers/bass traps to put in the two corners nearest my monitors. For these I'm using Joel DuBay's DIY design. I imagine those will help a bit.

I also have a ton of 2x4 sheets of ordinary Auralex/Sonnex style cellular foam that was given to me. I have several bags of it. Anytime I see mention of this type of foam, it's basically written off as worthless. Is that really true? I was thinking that I might cut it into pieces and use it to do "superchunk" style treatments in some other corners in my room. My idea was to put the faces of the foam together, so that the 2 sheets would interlock, and then cut them into 8 triangles per sheet, then stack them together. I know it's not the density of rockwool or OC703, but is it it worthless?

Any opinions on this idea, or would it be better used in some other way?

Thanks!

Stephen

[Marc Alan Goodman]

I think the whole "worthless" thing really means "not worth the money". If you got it for free it'll definitely do something! And your understanding of it (better if you join two layers to make it solid) seems dead on.

[norton]

The foam is really only going to be effective on higher frequencies.... so it's not going to be much help in your corners. You'd be far better off treating your mix position front wall with the foam.

After that, look to your side and back walls and your ceiling.

All of the treatment areas you'd normally be looking to treat, rigid fiberglass will always be a better choice for the money and the performance... but if it's free, the foam will be much more helpful on your walls, than in a closet somewhere.

[allbaldo]

Thanks for the replies folks! I went ahead and made four 2x4ft x 4" rockwool absorbers for the corners of the wall. I might try some doubled up foam for the early reflection points and ceiling, and see where that gets me.