I believe I’ve gotten to the bottom of the stereo sound issue, seems to be related to the size of the EDID, I was able to get 5.1 working easily from an intel displayport using the adapter and my vertex, immediately plugged that right into my desktop and it went back to stereo. deleted some of the audio formats and resolutions from my EDID and now 5.1 is working and other frequencies are at least showing again.