Can in-wall speakers work for a corner HT set up in a really large room? A friend is building a new house with a huge Great Room (36 X 40 X 20). He can only put his 70" HDTV in one corner. He has been told by a local installer that he can use in-wall speakers and it will sound good because he can compensate with the surround processor. This sure does not seem possible to me. Does anyone have a good example of such a set up working well? I would think the corner location would not allow the in-wall speakers to give good sound reproduction at the listening position in the middle of the room, even if the tweeters could be "aimed" at that location.