Ethan or anyone else in the know...

[theletterq]

You have mentioned that 705 has a reflective backing that can be face into the room to reflect higher frequencies. My question is this:

If all you have to work with is 703 could you in theory cover one side of it with something like tinfoil before covering with fabric and then alternate these with non-covered panels?

 

[TexRoadkill]

705 is more dense and has better low end absorption. The high end diffusion caused by the foil is usually considered more of a compromise than a benefit. Putting foil over 703 would seem to be counterproductive in my uneducated opinion.

If you want to reflect high frequencies than just leave a portion of the wall bare or build some diffusors. If you want uniform mid absorption and high end diffusion than slot absorbers are usually recomended.

 

[Ethan Winer]

Q,

> 705 has a reflective backing <

Most rigid fiberglass is offered either with or without a metalized paper facing. For Owens-Corning products the faced versions have an FRK suffix. The facing does reflect some of the mids and highs, but it also enhances the low frequency absorption. So if you get the faced version you can install it with the facing toward the room to partially reflect the mids and highs, or toward the wall to expose the bare fiberglass and more fully absorb the mids and highs.

> could you in theory cover one side of it with something like tinfoil <

Again, it's more than just foil. It's actually Kraft paper that has a very thin foil bonded to it. You could probably fabricate something like that yourself, but the paper must be bonded to the fiberglass uniformly. That might be hard to do, since most glues don't stick well to rigid fiberglass. Contact cement might work, but it would have to be applied in a very thin and very uniform coating.

As Tex suggested, you might be better off just leaving some of the walls bare.

--Ethan