Tried a couple of extra subs today - I've been concerned about a lack of mid-bass volume, thought it must be room related, my 10" Peerless woofers are pretty good. Today hooked up a 6" pioneer & 8" Jaycar woofer via a passive 1st order line level xover, ~220Hz, at front of the room & to one side respectively. First track I played wasn't even bass heavy, just fiddle & piano - but the piano sounded almost life-sized - woh - I'm on to something here I thought, reaching for the heavy rock cds.... yep, it really works, drums & bass sound amazing. I didn't bother trying to refine the setup, just settled in for a good listening session, I'm sold on multiple subs...