Best place for a Sub in my mini Theater

I am finishing half of my basement into a 10’ x 20’ theater room. The viewing area is only 10’ deep. The tv and credenza will be recessed 2 feet so that they are flush with the wall. Picture them stuck in a closet.   I have in wall speakers for the fronts. Where is the best place for the sub and facing which direction? It’s front firing.

I can recess it into the wall and have it face the audience but it would be firing into a wall only 10 feet away.

I’m thinking maybe I should put it in the front left corner and have it fire towards the 20’ length but it may be blocking. A closet. 

The couch is against the back wall. What if I put it against the back left corner?

As you can see I’m a bit confused.