If you are doing anything besides 'direct throughput' the signal. even if analogue, is gonna be redigitalized to do any sort of eq, or 5.1 etc. So going via the Denonlink III is gonna save you multiple decoding, re-digitalizing, and then decoding steps.
The receiver is about as good as the DVD player.
(I own a Denon DVD5910 with a 4806 Denon receiver, via Denonlink III (the 5910 hdmi to the plasma screen)
The receiver is about as good as the DVD player.
(I own a Denon DVD5910 with a 4806 Denon receiver, via Denonlink III (the 5910 hdmi to the plasma screen)

