Just setup an IB using two DPL12. Sounds pretty good. I know that I need a BDF, but I am now wondering if I need to look at some room mod. As I said, it sounds good, but after listening for a couple of hours there is a constant and annoying freq. Almost boomy. I didn't have this with a single sealed unit, any thoughts. Were is a good place to start learning about room modification. ie sound panels and where to locate them.