On the Oppo smartphone, the audio is played back over two separate channels (stereo), which gives us a better listening experience.

If, for example, only one headset is used, stereo playback can be a disadvantage, since the same playback does not necessarily occur between the two channels.

ColorOS offers the possibility to change the playback from stereo to mono audio. Both channels are combined into one. The same audio content is played back on both listeners.

Android 10 | ColorOS 7.0
Step 1:  Open the  Settings
Step 2:  Tap on  Additional settings
Step 3:  Tap on  Accessibility
Step 4:  Enable or Disable  Mono Audio
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on Accessibility
  4. Enable or Disable Mono Audio

Oppo Instructions