I know this is an old topic, but I came across this in google search. I am having this exact same problem with my late 2014 mac mini connected to a marantz av8802a via HDMI . No matter what I have set audirvana sents 7.1 to my Marantz, I also have Kodi installed on the same Mac and it functions correctly, sending 2.0 to the marantz when it is a stereo source and 5.1/7.1 when the source call for it. Has anyone come up with a solution in audirvana a year later. I posted on the Audirvana forum but I dont think I will get an answer.
