So, now that my first project (Tempest AA) is well under way , and with a new home project, I was thinking about building a sub for my personal system. The Tempest will be used for a pair of piston speakers - I think they'll sound pretty good, since both are ported. But the next sub *has* to be a sealed design, since my second system has a sealed woofer (or so my logic goes). Considering I'd like the best extension possible, and that my speakers can't play too loud, *and* that I'd love to go sealed, what options do I have? I was thinking about the 12" Titanic. Is there any other driver I should be considering? Thanks for your help! Javier.