Wemfan and Finsup,
It looks like you'll be waiting 3-4 wks until you can figure out where to position them to sound best.
In the meantime, I'll give you some points to keep in mind when they do arrive:
1. Stand mounted monitors typically sound best positioned a few feet away from the wall behind them. I doubt they will sound as good if they're positioned backed against the wall. I suggest placing them, at least initially, as far away from the wall as you can while still being not in anyone's way walking in front of them. Just make sure the front of the LS50's are closer to you than the plane of the hdtv screen. You will almost certainly notice a decrease in sq if the speaker faces are behind the tv screen plane.
2. For lateral distance between the speakers, a good starting point is to position them as far apart as possible while still not obstructing doorways. If the music sounds like it is coming from points between the speakers, and not from the left and right speakers themselves, then leave them at this width. If not, then slowly move each speaker closer to the other in small increments until the sound seems to emanate from between the speakers.
3. Think of each of your speakers as corners along the base of a triangle and your head as the peak corner between the two base corners or points. Ideally your head, laying in your listening position, should be exactly between the left and right speakers. The distance from the left spkr to your left ear should be as close as possible to the distance from your right spkr to your right ear. This is critical in creating the illusion of a realistic soundstage on well recorded music. The goal most of us are after is a soundstage illusion that is wide, deep and steady. For example, on a well recorded acoustic track, the vocal might come from center stage, with percussion behind, other instruments positioned left and/or right without this illusion wavering.
You'll know your speakers are positioned properly when this goal is achieved.
4. It's easier if you have a helper; the helper makes small positioning adjustments to the speakers/stands, at your direction, while you listen for results at the listening position.- or vice versa.
5. There is another positioning method to the above called 'Toe-In'. Start with each speaker pointed straight ahead with no angle. Experiment by angling each speaker inward incrementally toward your listening spot to find out if this improves sound staging or not.
All these small adjustments to positioning are trial-and-error; the more attention and effort, the better the results. If you cannot achieve a good sound stage using these steps, your room acoustics may need analyzing and corrective room treatments. We can discuss this later if needed.
6. This is the final, and definitely the most important, guideline to follow: All of the above steps need to be done either well before your search for a life partner or a considerable time after you've met. Obviously, any sane person observing you perform the above obsessive-compulsive and rather pathetic ritual, is going to have a very strong urge to flee.
You've been warned,
Tim