Try this solution
Disable transparency mode
You may have Transparency Mode enabled. To disable the feature just triple-tap either earbud bud. Or manually turn it off in the Melomania app.
Make sure your earbuds fit your ears correctly and that you have a good seal
Your earbuds give the best sound experience when they fit properly. You may also want to push the earbuds slightly further into your ear. Watch the video to learn how you can try different ear tip sizes and ear fins to fit your ears perfectly.