Has anyone has read Harman Audio's research on subwoofers? http://www.harman.com/wp/pdf/multsubs.pdf It's a pretty easy-to-read essay that addresses the issue of bass optimization while taking into account real-life limitations. I remember that Dr. Hsu has often recommended placing the subwoofer right next to the listener for maximum bass accuracy. Unfortunately, such ideal physics doesn't translate into something practical. Not many people want subwoofers and wires in the middle of their living room, which is probably why that idea has never taken off. Back in the 1990s, I figure Tom Nousaine legitimized corner placement of subs on the basis that it will excite the maximum number of room modes and generate maximum SPL--ie. it's the best compromise. From what I gather, the main tradeoff of corner placement is that it yields fairly even frequency response only for the person seated at the calibrated listening position--i.e the sweet spot. I think most of us are willing to live with this tradeoff. Apparently, the folks at Harman have discovered the magic formula for subwoofer performance (in a rectangular room), which is four subwoofers, one against the midpoint of each wall, creating even frequency response for virtually everyone in the room (a larger sweet spot) while producing ok SPL (though less than 1 in the corner or 2 at opposing midpoints). The second best method for balancing even frequency response (though I see it as the best it provides almost as much SPL as 1 in the corner and a sweet spot almost as large as 4 placed at the midpoints) with max SPL is 2 subwoofers, one at the midpoint of opposing walls. Floyd Toole also recommends equalization when this is all done (using a parametic equalizer). Obviously four subwoofers is less attainable for those of us who must work for a living and stack other things in our home theaters besides gear, but it would be interesting to hear from anyone who has tried this method. The validity of their research—who am I to question their scientific credentials—is making me wonder which subwoofer would be best to buy if I wanted to eventually add another so I'd have two subwoofers at opposite wall midpoints instead of just one in the corner. What do people think? Two boxes or two cylinders? I am currently looking at buying a SVS 20-39 PCi. Or just buy the best single sub I can afford right now, and worry about which pairs to get when I'm lucky enough to afford such a setup?