Soundlab speakers produce nearly as much output from the rear as the front, making the distance from the back wall far more critical than the sides. The distance from the rear wall is determined by a number of factors, including toe in, wall treatments, and ceiling height. I keep my U-1's about 5 feet from the rear wall, even with RPG panels and Tube Traps in place. The single most important and overlooked adjustment on Soundlabs is the vertical alignment. From the factory, they tend to lean backwards (especially the U-1). This destroys the focus of the high frequencies, sending the highs well above the normal listening height. This effects not only tonal balance, depth and soundstage, but the voice and instrument imaging as well. With the original factory feet, the U-1 is out of plumb nearly two and a fourth inches. Floor level must be considered at this point as well, an out of plumb floor by only one fourth of an inch, when multiplied out to the top of a seven foot speaker, produces huge errors. After the vertical is right, it is fairly painless to set the toe in. Simply sight thorough the speaker from the rear, aiming for the center listening position. Use the fourth cell, counting from the wall side of the frame. Sight with a horizontal rib that closely matches your head height in the listening chair. More than half the time, this gets the toe in dead on, leaving only the wall distance as a final tweak.