If you burn in an earphone, make sure to connect it by the highest quality of cables. I suggest anything over 400$ - that should do it. But make sure all burn files are at least 16 bit FLAC. Not ALAC, not WAV, not OGG - they must be FLAC. Otherwise, your earphone could end up stunted in its FR.
I would also suggest hooking it up to an amp from one of Headfi's sponsors as those will by far, be the best way to burn a pair of new earphones in.
People who suggest just listening to earphones, when that certainly is not what they were designed to do, are mistaken. An earphone is meant to sit next to a source, occupying space and blasting music out at slightly louder than normal volumes for hundreds of hours. This process, like calibrating a laptop battery should be completed every couple of months. Failure to do so will mean a build up of memory in the earphone.
None of my earphones ever ever get time in my ears other than about 5 hours per week. Then while they are rotating in burn in along with my troublesome sources, I listen to a different earphone. But not a one has had less than 600 hours of burn in before I listen.
To prove it is a reality, I test it with a new earphone of the same type. Completely different. In fact, even the expensive IE8 sounds worse than an iPod earbud when out of the box. Some may chalk that up to manufacturer anomaly - hogwash. It has everything to do with vibrating the speakers millions of times - then and only then will earphones sound the way they are meant to.