My speaker builder suggest the speakers sound best when about 12 feet apart and around 3 feet away from the side walls.With that said I whould need a room about 18' wide.He also said that they sound the best when the listening position distance matched the width distance so that would meen about 12' away at least.I always like when speakers are out from the back wall,in my current setup the speakers are about 7' from the back wall.This sounds best to me as it gives me a great sense of depth.thats was behind my logic when I came up with the idea of such a big room..Ohh the room will be sheetrocked ,the concret will just be the foundation..I wish I could model my room after the room down at OvertureAudio in Delaware.No matter what I here in that room it always sounds perfect..