Sounds like Newbee hit it right on the head. If you listen to a well balanced system, you can play it really loud and not notice it until you try to talk to the person next to you. Her percieved decrease in volume probably means your have brought your system to a new level.
wife's observation
I have a Rotel RC-1070 pre and RB-1070 amp which power a pair of B&W804Ns. I recently replace my standard 14 ga speaker wire with 14 ga 4 wire (65 strands/wire OFC) and biwired the 804s. My lovely wife has commented that since the switch the sound level has dimished, meaning it is not as loud at the same volume setting as previously observed with the standard 2 wire speaker cable. Is this possible? i can't really tell a difference since we rarely go past 33% total volume. Thanks guys.