Sound only on one side of the car

[Chief Underverse]

Hi Adrian, I am having the same issue only it is with the fader setting. I get no sound from the rears when fading to the back. I looked for the well hidden mono setting and I can't find it anywhere. I have the JY-VQ131N4GN Android 10 with Jan 2021 firmware.

Can you tell me where this setting is located?