No TV sound

Change HDMI Audio from Auto Detect to another setting on the XBOX One.

If your are running the HDMI to the receiver and then to your TV I would guess it's the receiver fault. If it's running HDMI to your TV then using its optical or coaxial SPDIF out then I say it's the TVs fault. Either way it should work and not switch between
stereo and surround. The dashboard and often the main menu in a game will just use the left and right channels and then switch to using all channels when the game is running.



I know if you have both the optical out running to surround the HDMI will still carry a stereo signal along with it which is why you need to mute your TV. I haven't tried it, but possibly disabling display discovery on the 360 might keep it from even trying
to send the audio signal. Normally the EDID reports if a display has speakers and the 360 will switch to HDMI+A. Haven't checked so might be an option to just select HDMI without disabling the display discovery.

There really shouldn't be any PQ/AQ issues caused by running video & sound through HDMI. That's HDMI's job. It sounds like your PQ problem is a either a setting in the 360's menu or poor picture calibration on your display. The issue of the sound randomly
switching from 2 channel to 5.1 channel modes may have to do with your having the 360 connected to the TV via HDMI. I'm guessing you have the 360 set for 5.1 channel operation since you're running an optical cable to your receiver? Since HDMI is a two-way
connection, the 360 may be detecting the TV as a 2-channel device, causing confusion with your manually input 5.1 selection. I may be way off base though, as I've never run into this issue (and never had to diagnose it). The best way you could run your setup
would be the way I'm running mine... 360 HDMI to receiver, then receiver HDMI to display. If your display has an audio output, you could try running everything via HDMI to the display (which you are doing anyway), then running the audio from the TV to the
receiver. My Bravia has an optical output, but I prefer running HDMI to the receiver first as it's simpler connections & operation.

Found this:

1. Update firmwares for TV, XB1S & Sound bar.
   
2. XB1S HDMI OUT (to TV) goes to Sound bar HDMI IN. (DOES NOT GO TO TV)
   
3. Sound bar HDMI ARC OUT goes to TV HDMI ARC.
   
4. TV AUDIO set to PCM. TV VIDEO set to ARC.
   
5. Sound bar audio set to HDMI IN. (NOT HDMI ARC)
   
6. XB1S Video set to 4K UHD.
   
7. XB1S Audio set to ATMOS.
   

*Most importantly, XB1S HDMI OUT (to TV) DOES NOT GO TO TV, BUT GOES TO Sound bar IN! XB1S HDMI IN Should NOT BE USED!

System sound and game sound work normally, Blu-ray/DVDs don't work on either sound or just tv. I also tested it on my other 4k tv an no sound for Blu-ray/DVDs.