Hey Jay,
I didn't think anyone had a situation similar to mine. How far is the back corner of the speaker closet to the wall from the wall? Looks like that corner is almost touching.
My setup is in a corner except that the right corner is the backside of a staircase going up. Under the stairs is open with a curtain hung where a wall would be if it was closed in. Then the wall of the staircase cts back between the right side of the mantle and the switches so that wall is parallel with your left wall. The back left corner of my right speaker will will be close to the stair wall just like the back corner of your right speaker. That staircase is part of the foyer so my right speaker will pretty much be sitting against that wall in the foyer with about 10' behind it to the front wall of the house.
I know I should just get a pic. Where can a draw up a plan from the internet?
