[hoppel118]

What do you mean by autochannel? PCM?

I have a Sonos Arc Soundbar and an LG OLED65C9. Dolby Atmos TrueHD works fine. The Sonos Arc doesn‘t support DTS, but it should work with an other soundbar/avr.

What did you configure in the enhanced sound settings at the android os level of your nvidia shield tv?

I had to use the option „automatically“ under „choose formats“. It didn’t work, when I choosed the supported formats manually. (Sorry, I don’t know the exact englisch menu names. My android user interface is in german.)

Regards Hoppel