I have a Denon 988 receiver (pulling this off the top of my head, got it used on Amazon a few moons ago) and I output from my nVidia HDMI to the Denon and let the Denon sit there in PureDirect mode so I get 2 channel (not Pro-Logic II) when I'm playing 2 channel and I get "multi channel in" on the receiver when I play a movie. I use WASAPI out of course. My Denon is just a pre/pro, I route out to a separate 5 channel amp for the main 5.1, I guess the Denon powers my 2 rear surrounds for a true 7.1 setup so I guess it isn't entirely just a pre/pro.
In any event, the SQ is fantastic in this setup when I play a PCM rip of SACD, 24-bit FLAC, etc... FWIW, I have Audyssey turned off but will start dabbling in REW here soon as I have everything I need to get going on that, just lacking some knowledge and understanding. There is nothing "wrong" with liking the sound with DSP influences like Audyssey, Dirac, ARC, etc... Those function as correction for phase anomalies, time alignment issues that a tape measure can't fix, and, to some degree, room modes. They WILL improve the sound. They do not work like the DSP settings of "Concert Hall" or "Jazz Club." I guess my point is - if YOU like the sound, who cares how it got to that point? Most people would not like perfectly flat response in a dead room. Music needs soul and character, not just proper room setup.
HTH,
Todd