The only solution for now is to use the DP2HDMI adapter?Rules: • Profiles need to contain at least your primary system to assist others with helping you.
Good to know.
MSI GTX 970 Gaming 100me -> HDMI audio works
Zotac GTX 970 -> HDMI audio works
Gigabyte GTX 970 -> DP to HDMI adapter needed
ASUS GTX 1070 Founder's Edition -> HDMI audio works
Zotac GTX 1060 3GB -> DP to HDMI adapter needed
Gainward GTX 1070 -> DP to HDMI adapter needed
As we can see, HDMI audio getting enabled or not seems to be some kind of Pot-Luck.