Recently bought Denon 4520; quite satisfied with its surround effect but quite disappointed on the performance of 2 channel music on Denon 4520 when comparing with the Burmester matched with Metronome.
I can't accept using Denon 4520 alone in listening 2 channel music or 2 channel movie at all if my Burmester is still in use.
So if the Diablo has AV by-pass function just keep it for greater music passion and AV output for front speakers.