I'm curious as to whether the RB 81 is as good as the RB 75. It appears to me that the RB 81 may be a derivative of the RB 5/RB 35 level as opposed to the 75? I have been told that I must relegate my KLF 10's, etc to the "mancave" and replace them with some bookshelves and inwall surrounds in the family room. The room is 24'x24' with vaulted ceilings. Sub duty is performed by a 15" Rythmik Servo as my SW 12II quit on me last year. I like the efficiency of Klipsch, especially in this size room, but I've not been a big fan of most of the Reference line. I have found the RF 7's to my liking, and figure the RB 75 should be close to that. If the RB 81 is more like the RB5, I think I'll have to switch to Paradigm Reference even with the greatly reduced efficiency.