Plug your Earphones to 2-3 smartphones and they should work fine. Sometimes earphonez do not connect to mobiles from lenovo.
If they are Bass enabled then run them on Bass and feel the music the voice or sound should not get cracked.
Check that the earphones you are buying are comfortable to your ears as some earphone causes ear pain.
Beware from buying fake and cheap earphones as they do not last long and within days or week they are of no use. So buy some which has a great value for the money you pay.
Also check the mic and button are workinv properly or not buy calling on your smartphone.