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.
Speaker Placement
This is a tough topic for the newbies, and even some of us old guys. Regardless of the theory and even the software available, I suspect there is much that the more experienced among us could pass on with this problem. As you shift your speakers closer to the optimum position, what do you hear? What do you hear when the speakers are too close to the front wall, or when they are too far out? What do you hear when they are too close together and need to be moved further apart? What do you hear when they are too close to the side wall? What effect does toe-in have? What strategy do you employ to dial-in a new set of speakers or a new room? I am sure Albert Porter could help us all on this one. I will post some of my experiences if this topic gets rolling.