Sorry it took a while to get back to you. Computer problems.
What are your current screen dimensions? How wide is your screen wall?
Unless you want to spring for an acoustically transparent screen (SeymourAV, SVS, etc.) and in-wall left/center/right speakers behind it, you'll need to get three identical speakers that will fit underneath your screen. That's not ideal, but you have to work with what you have unless
you're up to rearranging some things around in your basement to make it more conducive to a home theater environment.
The former idea with AT screen and in-walls would be a lot better, though more expensive, than the latter since it would elevate your speakers to a more normal listening height with their tweeters closer to ear level.
Another pointer: you really don't want your seating right up against the back wall. It makes it less than ideal for proper surround sound.
L-shaped seating arrangements are also not recommended as those people sitting on the sides will have to sit awkwardly and crane their necks to see the screen properly.
The Arx A3 is too tall to go under your current screen. Try the A1 bookshelf instead.http://www.theaudioinsider.com/produ...products_id=65