Did i just get crappy earphones?

I just got some head phones, they were only about 5 bucks, but i usually buy cheap headphones....[[i know i know, im cheap.]] and they work fine... Well in these, when i listen to music, i can hear the back round instruments alot louder than the voices? is there a settin in my computer or anyway to change this... or did i just buy extra sh!tty earphones?