Awaiting my 30x48 Longmill and making an enclosure. I have a bunch of Rockwool from an old project. Specifically, Rockwool Mineral Wool 60. Sound absorption is amazing. Any reason I shouldnt line nearly the whole thing in the rockwool? Might be a dust magnet? Seems like it has a great fire rating. I think it absorbs sound better when it is exposed to the sound vs being between two walls. Perhaps I am wrong?