the difference between roll and rigid fiberglass

[mixmkr]

is?

what is the advantage of 703 (or like product..Roxul, etc) over using something even like some 6-8" roll or batt owens corning, compressed to 4 inches in a framed bass trap?

 

[Farview]

Don't quote me on this, but I was under the impression that 703 was equivelent to 12 or 16 inches of the fluffy stuff. You wouldn't be able to compress it that hard without effectively keeping it from vibrating. That would defeat the purpose.

I've also priced it out (when I was thinking the same thing you are) and the 703 is about the same price as the equivelent amount of batting. So you don't save any money and only add agravation.

 

[RICK FITZPATRICK]

I was under the impression that 703 was equivelent to 12 or 16 inches of the fluffy stuff.

No, it isn't. The deal is DENSITY vs thickness. Even with 12" you won't get the same performance as 4" of 703, simply because of the density, which translates into GAS FLOW. The "interstices" of the fiberglass in 703 are more compact, which means the air molecules have to move around thim MUCH more than in batt insulation. Also the thickness determines the optimum absorption coefficient at a given frequency..ie, the thicker, the better LOW FREQUENCY absorption, because of the 1/4 wavelenghth therom...ie, the maximum velocity is at 1/4 wavelength, the minimum is at a boundary(the wall)The friction created by air moving within the interstices, is transformed into heat, but don't try to boil water with it.