on an android device like the LG, the sound is played back in stereo on headsets and headphones by default. if you now use a headset for two, for example, each with one headphone, the audio playback will be different. to prevent this, you can activate "mono audio" in the LG smartphone's helper controls. this combines the two audio channels into one, so the same sound is played on both earcups.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  General
Step 3:  Tap on  Accessibility
Step 4:  Tap on  Hearing
Step 5:  Tap on  Audio channel
Step 6:  Choose between  Mono  and  Stereo
  1. Open the Settings
  2. Tap on General
  3. Tap on Accessibility
  4. Tap on Hearing
  5. Tap on Audio channel
  6. Choose between Mono and Stereo

LG Instructions