Here are 3 very good methods for speaker placement to try. I found the Cardas method to be the best for my particular room and speakers. Different rooms and different speakers all react diferently.
It is a simple formula. The speakers are placed 1/3 of the length of the
room from the wall behind them and 1/3 the width of the room from the walls along side them. The listening position is then placed 1/3 the length of the room from the wall behind it. This placement reduces speaker interaction with the room to an absolute minimum. The obvious problem is space and aesthetics. Works well if you
have a dedicated listening room or HT.
2)The Vandersteen Method.
This second formula is a little more complex but, doesn't require such a sacrifice in room function and aesthetics. It is for a typical rectangular room. Measure the length of your room and convert it to inches. Now divide that by several odd numbers. I would suggest dividing by 3,5,7, 9. That should be enough. Now take a piece of note book paper or graph paper and put it down in front of you so that it is horizontal, letting the right edge represent the wall behind your speakers. Now draw a vertical line for each result of the division. (ex., say your room is 216 inches. 216/3=72, this line would be furthest away from the right side and marked 72". 216/9=24, this line would be closest to the right side of the paper and marked 24. The other lines would be between these line and marked with their results). Now do the same measurement and division with the width of the room. Now this time your lines will be horizontal. For each result you draw two lines, one away from the imaginary left wall(top of the paper) and one away from the imaginary right wall (bottom of the paper). Mark each line with the result of the division. Each place a horizontal and vertical line intersect is a optimum spot for minimal room interaction. This gives you many options for your room.
3)Golden Ratio (The George Cardas method).
Still using your room dimensions in inches try using the following method. Place speakers using the distance from the center of the woofer face to the side wall as your measurement. The side wall node closest to the speaker is the most important, followed by the rear wall, and then the opposite side wall.
RW= Room Width
Speaker distance to side wall= RWx.276
Speaker distance to rear wall= RWx.447
Speaker distance to opposite side wall= RWx.724
Speaker to speaker= RWx.447
Speaker distance to listener= (speaker to speaker)x1.1 or 1.25
A variation is; Ceiling Height (CH)x.618 for the speaker to side wall measurement.
The "formulas" only represent a starting point. You may have to move the speakers and inch or two after the initial placement due to windows, furniture, door openings, and other things that can interfer with the sound.
If properly placed your speakers should need little if any toe-in. In general you toe-in your speakers to eliminate some of the wall reflection that occurs when you have to place them in a corner or back up against a wall.