Jon, I have a down-firing sub, too. Although - since my kids are now in/near college - I might be due for an upgrade.

I still think you should put the surrounds behind the seating area. My system was set up in a ~11x14 room with the seating on the wall opposite the display on the LONG sides. I had the QS8's behind/above, and thought it was just great.

Jon, I'd suggest that you separate the surrounds wider, say about 8 feet. Keep in mind that the surrounds in a 5.1 setup are side surrounds(not "rear")and play the side surround channels, even if they're mounted on the back wall. So, they should be separated as widely as possible, so as to give a primarily side, rather than back, effect. They should be about 2-3 feet above ear level and pointed directly forward, not aimed at the listening position.

Because the listening position is almost up against the back wall, it's unlikely that back surrounds in a 7.1 setup will add significantly. I suggest that generally at least 4 feet of space be behind the listeners for back surrounds to form a rear sound field.

Surrounds out to the side about as far as possible on the rear wall has good effect for 5.1. I have mine on the side walls with my seating area out about 18inches from the back wall and this works for me, I have pics in my link below.

Thanks guys! I'll make rough up some stands with 2x4's and experiment a bit before the final mounting.

Also, I'd just like to say that this is a great forum community. It's nice to have folks who are passionate and so willing to share experience and ideas. Cheers to you all!

That's a good idea! Just so you know, the THX specifications for the side surrounds actually recommend that they go on the side walls a bit forward (towards the screen) from the listening position. However, this basically assumes that you'll be using one or more rear surround on the back wall. Nevertheless, I'd try both -- and give preference to the side walls especially if I thought I'd ever possibly want to install the rear surround(s) for a full 7.1 or 6.1 system. If you're sure you never will, or don't mind potentially moving them, then the rear wall is fine too.

Your description is very similar to how my room is setup currently. My rear seating row is up against the back wall with the rear surrounds mounted as you mention. They are apart about the width of the couch. The side surrounds are mounted a little higher and angled down toward the listening room using the Axiom mounts. Don't worry about not having one wall open, at one point before I enclosed my theater will walls, I had 2 sides wide open.