Dan, thanks for the dose of reality in pointing out the expense of the PR solution, which I thought would get out of hand. After all, DIY is not only about better than commercial performance, it's about low cost. I'm leaning towards sealed, myself. I'd like to have a musically fast, perfect sub that would also do justice to movie LFE's. Brian, you're right about poly cones - they just aren't very good in any driver, sub or bass or midrange. Jack, thanks for backing me up on suggesting two drivers, one optimized for sealed, the other for reflex configs. Let the games begin!!