Lots of interesting things being said here.
I spent the majority of last night fooling around with placements. I tried nearly eight or so. I get get a boom, but it's hard without being muddy. I got sick of moving it around and just gave up for now. I placed one in the right corner in the room, and the other sub in the left.
An interesting point though, I couldn't connect both subs via the subwoofer out on the receiver. I got a bad hum through both subs when connected with a "Y" connector. So I hooked one up via the high left channel. So it's curious to have the dedicated LFE, and have the second sub firing the strictly the left channel bass. Made for an interesting gaming experience.
So I don't know what to do about placement. Certainly nothing seemed obvious. My couch sits against the wall. That wall is just framed with drywall. The opposite side of the wall is the furnace room. I wonder what it would sound like if the sub was in the room behind the theater, directly behind the couch. Thoughts? I would just try it, but you know... hole in the wall.
