For those unlucky fellows who cannot get HDMI audio working on Nvidia 9 series Maxwell even after using HDMIaudio.kext as well as Toleda/Rehabman SSDT script I have come up with a wacky solution.
Buy a passive DP1.2 Male to HDMI 1.4 Female adapter. Those are cheap under $10 (I gone mine for $4). Plug in HDMI cable from your receiver into the adapter and plug the adapter's DP to your Nvidia GPU's 2nd DP.
1st DP should always be used by your primary monitor assuming you have 2 monitor setup....
Strange GTX 970 HDMI audio solution for Sierra
Buy a passive DP1.2 Male to HDMI 1.4 Female adapter. Those are cheap under $10 (I gone mine for $4). Plug in HDMI cable from your receiver into the adapter and plug the adapter's DP to your Nvidia GPU's 2nd DP.
1st DP should always be used by your primary monitor assuming you have 2 monitor setup....
Strange GTX 970 HDMI audio solution for Sierra