If you follow the Cardas formula, you may wind up with speakers way out near the middle of the room. Maybe not too practical if it isn't a dedicated listening room.
Another method seems to work well for me. I've seen it called the "Allison Rule":
"The Allison rule basically states that the distances from the woofer to the floor, woofer to the side wall, and woofer to the back wall should be as different as possible. To accomplish this, one would apply the following equation: Middle distance squared = shortest distance multiplied by longest distance."
(Don't know where I found this, maybe in an Audiogon discussion)
Once the speaker positioning is done, place the listening chair to form an equilateral triangle. Tweak to taste.
This method is flexible because it allows you to swap which ones are the short and the long distances. For the woofer to side wall measurement, you might try starting with the Rule of Thirds. But even if you move the speakers farther apart than the RoT dictates, you still can apply the Allison Rule.
Another method seems to work well for me. I've seen it called the "Allison Rule":
"The Allison rule basically states that the distances from the woofer to the floor, woofer to the side wall, and woofer to the back wall should be as different as possible. To accomplish this, one would apply the following equation: Middle distance squared = shortest distance multiplied by longest distance."
(Don't know where I found this, maybe in an Audiogon discussion)
Once the speaker positioning is done, place the listening chair to form an equilateral triangle. Tweak to taste.
This method is flexible because it allows you to swap which ones are the short and the long distances. For the woofer to side wall measurement, you might try starting with the Rule of Thirds. But even if you move the speakers farther apart than the RoT dictates, you still can apply the Allison Rule.