Earlier advice stands...
you could, if you choose to, experiment by moving it a little away from the Sofa, and perhaps even tuning it 90º to fire away from the back.
Towards the first suggestion, a few inches can make a difference in performance and could be useful to the performance... that just depends on your room.
To the latter suggestion, you may not even notice a change and I only make the suggestion as it is seemingly tight up on the wall and bent cords can break, thus may alleviate strain on the cord.connection.
You can futz with it if you want, but nothing other than actually moving the Sub around more than just-angling-it will likely affect anything.
