Here is an old drawing back in the days of my 500, but should give you an idea. The 600 is now placed on the left wall right below the first wall treatment panel close to the front left speaker. I was thinking about putting the 600 back up front under the center channel since it looked cool. Then, get 2 or maybe 3 more subs.
One would go along the left wall, one would go on the shorter right wall below that panel, and the third could be daisy chained off the left one and maybe be placed along the back wall. My drawing is a little off as the back window and walkout door should be moved a bit to the right, so I have some wall back there for a 4th sub. The bad part is I would have a long coax going along the entire length of the side wall to the back wall.
