I guess my definition of "muddy" would be as follows: too much squawk in the vocals
they had Dave Matthews queued up at Ultimate Electronics going through a pair of Infinity Beta 40's. The salesman dialed up the Denon 2805 and the Yamaha RX-V1500.
On the 2805, you could hardly understand the words to "What Would You Say". It sounded like the teacher from Charlie Brown was singing, and none of the DSP's would clean it up much. No one will ever confuse the Dave Matthews sound with Robert Goulet for crisp and clean, but you should at least recognize the words as English...(ok well Southern Fried English). It was basically no improvement over the Sony STR-DA995 I'm running now.
the Yammy RX-V1500 did a much better job of cleaning up the sound.
the salesman blamed the sound board, the connections, just about everything in the room, claimed they hadn't optimized the Denon for those speakers, etc and he may be right, who knows, but the Denon 2805 was $ 150 more than the 1500, so what would you believe ?
I have a Yamaha on order. Just one man's opinion.