DIY bass traps and absorbers

[tweeksound]

I was shown and found some info on creating your own absorbers and bass traps using OC 703 rigid fiber.
They recommend using 2 layers to get 4".

I was wondering if there'd be any loss of effectiveness or gain in effectiveness if I use 13" R-38.

Would that extend the absorption to lower frequencies?
Would these be good for putting in the corner for low frequency absorption?

I assume if I space them from the wall it allow double absorption of extended freq's from the direct sound and first reflections.

I need a cheap and effective full freq. treatment.
Any advice is welcome.

[bpape]

The thicker the better in areas which are going to be asked to do bass absorbtion. It's about a breakeven at approx 8" of thickness vs OC703 with a slight loss from about 60Hz down.

On the walls, there's no way I'd put up something 13" thick and compressing it gets you right back to a thinner material. In those cases (for reflections on the side walls), 2" OC703 or 2" 3lb Acoustical Cotton are the best options.

Bryan