Solving playback issues

[R2H72]

I just bought a Roku Ultra LT to connect to my 2021 LG OLED C1 TV and Onkyo TX-SR93 AV receiver. Using all HDMI 2.0 cables and ARC between the TV and AV. The Roku is directly connected to the AV receiver. I find that the Roku is decoding Dolby Atmos and DTS audio correctly which my Roku streaming stick had stopped doing for some reason. I have two problems. When I set the Roku display type to 4K HDR Dolby vision, I get a proper TV display and everything is fine. At power off and subsequent restart, the Roku reverts back to 1080p Dolby Vision. Unrelated(?), I also get a hum from my subwoofer a couple of minutes after shutting everything down, which requires me to turn the sub off rather than leave it in standby mode. It seems to be getting a signal from the Roku which is still connected to power, even though its light is off and it doesn't seem to be streaming. Any thoughts?

[RokuDanny-R]

@R2H72 

Thanks for the post.

Do you experience this same issue if you connect the Roku device directly to your TV and not through the AVR?

Please keep us posted what you find out and we will be able to assist you further.

Thanks,
Danny

[R2H72 · Accepted solution]

Both problems now solved. The video problem was solved by connecting the Roku output directly to the TV's HDMI 1 port and a second cable between its HDMI 2/ARC port and the ARC port on the AVR. I now get Dolby Vision video on the TV and Dolby Atmos audio from the AVR. I'm not sure why this was necessary since my AVR is capable of decoding Dolby Vison, but whatever works. Enabling CEC on the AVR also allows the Roku remote to control power and volume for both the TV and AVR. The subwoofer hum was a separate issue caused by a sub-standard cable that I had made myself, though I'm not sure why it just now appeared as a problem. I think it was picking up AC interference from proximity to several power cords and a good shielded subwoofer cable took care of that.