This function can send the audio of the left and right channels to each earbud so that each ear can hear the audio signal of the two channels, and there is a left and right channel balance volume balance setting, and you can adjust the volume by sliding the button.
The left and right sound levels are recommended to be turned off for users with normal hearing (this feature is turned off by default).
Setting method:
realme UI 1.0 and above versions: Settings > Search Mono Audio > Mono Audio.
realme UI R & Go & T & R & U Edition: Settings > Accessibility > Audio adjustment > Mono Audio.