Maybe you had a bad reference and a well tuned pair of earphones sound bad to you at first, or you had a good reference and the earphones are badly tuned but you get used to the sound after a while, and now that becomes your reference which is a bad one.

Or you never had a good reference and the new earphone won't improve the situation. Hence you don't know what a well tuned earphone sounds like. You still get used to it.

These are your possibilities.