I am new the AV/Home Theater. I purchased an LG OLED65C9PUA TV which I have connected via ARC to my Yamaha RX-A780. As expected, when I power up everything from my Xfinity XR-11 remote both the TV and Receiver power on and I am able to change the channels on the set top box adjust the volume of the receiver. The problem is that apparently the ARC channel makes the receiver assume that the audio is going to flow from the TV rather than from the set top box and automatically defaults to "AUDIO1" and there is no sound until I manually change the input to HDMI2 (the Xfinity connection). Of course once I do that, everything works fine - until I shut it off, and then it defaults back to "AUDIO1" the next time I turn on the TV. I have looked at every setting on both the TV and the Receiver trying to find a way to make the system default to HDMI2 to no avail. In short, I just want to be able to click the Xfinity remote and have the system send the picture to the TV from the set top box while capturing the audio from the same set top box. 90% of the time, I am watching TV/NETFLIX/AMAZON PRIME or listening to music on PANDORA or AMAZON MUSIC via the Xfinity box. On the rare occasion that I want to initiate something from the TV apparatus, I am more than happy to change the input.