I have a question about room treatments. As I mentioned previously, I didn't get around to canceling my order for the mineral wool boards. I have a case of 6 Roxul Rockboard 80, and another case of 6 Roxul Rockboard 60 on their way now. The 80 is 8 lb/ft3 (equivalent to OC 705), and the 60 is 6 lb/ft3 (equivalent to OC 730). I was planning to create two 6" thick bass traps using the Rockboard 80. Do you guys have a recommendation of what I should do with the 60? Should I build 2 less dense bass traps, or should I build some broadband absorbers? If I go for broadband absorbers, should I go for six 2" thick or three 4" thick panels.
Also, the back wall near where the sub is set up rattles quite a bit when things dig really deep (think the skadoosh scene in Kung-Fu Panda). Will placing an absorber back there help with the rattling?