Oppo
Turn Mono Audio On or Off auf Oppo
Oppo phones running Coloros mix audio in stereo by default, sending different parts of a signal to the left and right channel. That works fine with two working earbuds, but causes problems when only one channel reaches your ear, for example with a mono Bluetooth headset, a single earbud, or a hearing aid on one side. Dialogue, ringtones, or game cues panned to the missing channel simply become inaudible.
The Mono audio setting under Accessibility solves this by combining both channels into one identical signal played through either side. It works system-wide for media playback, calls, and notification sounds, so you don't need to adjust the balance separately for every app.
To enable or disable it, open Settings ➔ Additional settings ➔ Accessibility ➔ Enable or disable Mono audio. Turn it on if you regularly use a single earbud or mono headset, and switch it off again once you go back to a full stereo headset or speaker, since mono playback removes the spatial separation stereo mixing normally provides.