As per rules, please update your hardware profile to allow others to help you easierI Got the Nvidia HD sound working but can not control it in Sierra only can control it in my Monitor. Say no output.
Thanks for this - SoundFlower working on 10.13.6.MacOS doesn't have any controls for HDMI/external audio.
You have to use the volume controls on the TV or monitor you are connecting to.
Alternatively use a third-party app to get HDMI audio controls in macOS. SoundFlower was the defacto app a number of years ago, but development has halted. Free versions are still available but not sure if they are compatible with new versions of macOS.
Rogue Amoeba's SoundSource may be a viable option, but it is not free.