HELP; Acceptable Living Room Sound Treatment

My TV is on the side of the LR with a very high wall and the echo is terrible. What can I do to minimize the echo but keep it understated? My current listening room is my office and is really a room only for me so I can do whatever in there, but my living room is where everybody goes.

The sound system in my living room is not state of the art by any means, but I'd still like to tone down the echo and get the best from what I have now.

I thought about creating some kind of art with black poster board and some grey Acoustic Foam, the kind you can get from Parts Express. If might look fine if I hung it up high enough but not sure if it will or not.

Any advice would be appreciated.