This is extremely useful as I'm having the exact same issue. I changed HDMI to USB-C cables connecting my MacBook to my tv/5.1 sound system and could only get stereo sound. All connections in the midi audio setup and VLC player are telling me 5.1 is enabled and yet only stereo plays.

My Denon receiver also confirms the existence of only a stereo connection on the display when. It is connected. So I assume my (rather expensive) new HDMI to USB cable is stereo only. It is this model. It doesn't specify the number of channels it supports so I think you're right in that being a smoking gun for a stereo-only signal.

This is extremely useful as I'm having the exact same issue. I changed HDMI to USB-C cables connecting my MacBook to my tv/5.1 sound system and could only get stereo sound. All connections in the MIDI audio setup and VLC player are telling me 5.1 is enabled and yet only stereo plays.

My Denon receiver also confirms the existence of only a stereo connection on the display when. It is connected. So I assume my (rather expensive) new HDMI to USB cable is stereo only. It is this model. It doesn't specify the number of channels it supports so I think you're right in that being a smoking gun for a stereo-only signal.

This is extremely useful as I'm having the exact same issue. I changed HDMI to usb-C cables connecting my MacBook to my tv/5.1 sound system and could only get stereo sound. All connections in the midi audio setup and VLC player are telling me 5.1 is enables ad yet only stereo plays.

My Denon receiver also confirms the existence of only a stereo connection on the display when. it is connected. So I assume my (rather expensive) new HDMI to usb cable is stereo only. It is the below model. It doesn't specify the number of channels it supports so I think you're right in that being a smoking gun for a stereo only signal.

https://www.scorptec.com.au/product/cables-&-adapters/usb/90092-elk-05011-r?gclid=EAIaIQobChMI_cadm63m9gIV3ZJmAh1RPgQZEAQYAiABEgKVT_D_BwE

This is extremely useful as I'm having the exact same issue. I changed HDMI to USB-C cables connecting my MacBook to my tv/5.1 sound system and could only get stereo sound. All connections in the midi audio setup and VLC player are telling me 5.1 is enabled and yet only stereo plays.

My Denon receiver also confirms the existence of only a stereo connection on the display when. It is connected. So I assume my (rather expensive) new HDMI to USB cable is stereo only. It is this model. It doesn't specify the number of channels it supports so I think you're right in that being a smoking gun for a stereo-only signal.