I'm going to be placing a Polk RC6s speaker in my new bathroom ceiling. Ceiling is 3/4" thick plaster and lath and I've got 9" (an odd number, I know) of space above the ceiling before hitting the bottom side of the attic floor. How large of a compartment (e.g. speaker box) should I build around the speaker to create better sound?
Outside the box will be cellulose insulation and I'd like to insulate the entire box (attic above is unheated) to prevent condensation from occurring on the speaker itself during the winter.
I was planning to build the box out of sheets of 2" Dow Super Tuff-R insulation that are glued together to be airtight. Is that a good choice? Using it for the top too I could still get R-13 between the attic floor and the bathroom. Hopefully it'll stay warm enough to prevent condensation.