How do you have audio settings configured? Best practice is using pass through and automatic format detection. While my Onkyo supports Atmos, I rarely if ever experience it being used. Depending upon the source, most content streams in Dolby Surround though its easy to select other formats with the Onkyo remote. That said, if I choose custom rather than pass through, Atmos appears in the format choices which when you think about it is weird. I've yet to figure out how Roku engineered the audio settings, but it is what it is
Power User (film maker)
Mill Valley, CA
Jonathan
Roku Ultra 4800R; LG OLED55B7A, ONKYO TX-NR636, Panasonic Blu Ray, Definitive Studio Monitor 450 (L/R), Definitive LCR 2000 (center), Definitive 10" sub-woofer, Definitive surrounds. Motorola MB8600 modem. Asus RT-AX68U WiFi 6 router. Western Digital Power Line network adapters
