2 days back l connected 5.1 out of xonar d2x to 5.1 in of marantz avr.Comparison had mixed results.While playing movies, I certainly missed some settings in avr as audyssey is bypassed.The timing was missing in 5.1 clips.Yes some paid softwares do offer extra,but again you need good pc hardware for that.In music,I enjoyed xonar sound more than marantz's internal DAC.Both use Burr Brown dac chips.Xonar had better soundstage and better presentation.On other hand avr had little cleaner sound.I still remember old generation AVR used to be better than xonar.I have tried at least 8 different avrs in my setup

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