The only scientifically correct way to find the absolute best locations for speakers is using
the out-of-phase (speaker set up) track on XLO Test CD or similar Test CD or Test LP. All (rpt all) other methods, e.g., making speakers equidistant, making an equilateral triangle, using lasers, trial and error by listening, will be unable to find the absolute best locations. It would be like looking for a needle in a haystack. When the system is out of phase you should hear the sound coming at you from all around, with no particular direction. When that occurs, and it won’t happen overnight because the room acoustics if not treated interfere with how perfectly diffuse the sound can be on the out-of-phase track. Rome wasn’t built in a day. Anyway, be that as it may, when you get the out of phase track correct you will get the best sound when the system is IN PHASE. Everything else is a trade off. In some cases because the room acoustics are so bad, you might not even hear ANY differences when you move the speakers around. No one said it was going to be easy. Other locations might sound OK, but they won’t sound as good as the locations found using this out of phase method.