I have B&W 801S3's in a 13' wide x 22' length room. These conditions work great for me. The speakers are located about 2 ' off the side walls and 5' off the front wall. Also my listening chair is 5' off the rear wall. With my related gear and the right recordings the speakers will disappear.
Placing B&W 801s3 in Small Thin Room
Always wanted the 801's, and now, when retired and in small house I finally get some Series3, but my room is not ideal This is my room. The speakers are on the long wall which is 27' and has a vaulted ceiling directing the sound forward and down. So far so good. The bad is the room is only 15' wide. Right now I have the speakers (both base and swivel mid/high) facing forward about 1' from back wall with listening position chair up against facing wall. There is an archway that cuts out some of the listening wall and several alcoves that can be used to mix up reflections. I have expected seting the woofers at 30deg to back wall would reduce boom but it did not. Base is too strong and little slow, while top end is bright. Being driven my Krell KAV250p and KSA250.