I also added a second pair of 901's to my current set-up and was very pleased indeed. I had previously been using a pair of nice (but not 901 level nice) Yamaha's in the back for that 5.1 surround effect. That was ok when watching a movie, but when I would listen to music, their "direcctness" as compared to the 901's "spaciousness" was very noticeable and annoying to say the least. By adding a second pair for that end of the room, it was a night and day difference. With my eyes closed, I could no longer locate the speakers in the room. The sound is everywhere and equally distributed. And of course I think the quality of the sound is much improved also. Now at last I can lay into the volume on the big, fat Denon and not hear the rear speakers knocking themselves to pieces. As a matter of fact, I sometimes can't hear myself think… which is a relief sometimes. Some music just demands to be felt as well as heard. Good thing I own the house next door too.