What height is the tweeter up the speaker cabinet? My ears sit 42-46" off the ground depending on the chair. If mounting directly to the wall i'd say mount the speakers to that the tweeters are within that range of height, and then place the speakers so that the tweeters are anywhere between around 36-50 inches apart horizontally. That aspect depends more on the speakers' dispersion pattern and the distance away from them that you'll be sitting. The further away you sit, the further they can be spread.
