headphone jack problem background music plays but you cant here vocals

i plug in my earphones into my touch, when i play a song the background music plays loud and a little strange but i can't hear the words that the singer is singing (they are really faint). i tried it with a couple of different songs and earbuds/headphones and it gives me the same results. But without the earphones the music plays perfectly. i tried it with my ihome and it worked fine it seems that the problem is only with devices tat use the headphone jack.