1) Make sure both earbuds are worn correctly and on the correct ear (L on left, R on right).

2) Check that the mobile’s audio balance is in the centre and Mono audio is off (Android: Settings > Accessibility > Audio; iPhone: Settings > Accessibility > Audio/Visual > Balance). The path may vary by phone.

3) Gently clean the speaker mesh of both earbuds with a dry, soft brush – dust, earwax or sweat can lower the sound on one side.

4) Please once reset the earbuds and reconnect. If the issue persists on another mobile as well then RPU.