Looking to mount my new SB3 NHTs, and I'm wondering about how high to mount them.For the fronts, is it ok to mount them about 6 feet from the floor and angle them down? Or will this effect the sound? They have to be mounted on the wall, not on stands. What about the rears? Can they be higher yet, and should they angle down? The room is about 12x16ft, but the roof is all open concept and is peaked with about a 20 ft height.