Multichannel Output not working with HDMI receiver [Solved, Audio MIDI]

Hi everyone

Wondering if anyone has managed to make multichannel playback work using an HDMI connected receiver.
Using a Yamaha 1040 receiver connected via HDMI directly from MacMini using CoreAudio. Roon has the channel selection greyed out and set to 2.0 and downmixes all 5.1 albums (which are identified correctly as multichannel).

The same setup works fine using other software (e.g. Plex).

Any ideas?

Have you gone to the Audio-MIDI setup in the MacMini and set the output to multichannel? It defaults to stereo.

Try opening Audio Midi Setup, selecting the HDMI output and changing it to multichannel output from its default two channel.
Remove and re-add the device from Roon and you should find the channel selection no longer greyed out.

Thank you legends.

It now works.

I use Plex for movie playback and apparently, when Plex exits the default changes back to 2.0 in Audio MIDI setup.