1) Lower the volume a little – distortion at maximum volume can come from the content or the source app.

2) Test with different songs/apps and with another mobile.

3) Set the EQ back to a default mode (a Custom EQ with very high boost can cause distortion).

4) Keep the mobile closer – a weak Bluetooth signal can also cause crackling.

5) Clean the speaker mesh gently with a dry, soft brush.

6) Please once reset the earbuds and reconnect. If the issue persists then RPU.