Headphones with no vocals

I recently decided to buy some REALLY nice headphones, s-logic 650 ultrasone, if i plug them into my stereo they sound fine, but if i plug them into my computer some parts are faded to a ridiculous extent, like voices are almost non existent, i can barely hear them while the bass or other parts are clear and sound great. I dont think the headphones are broke in any way because they are a week out of box and they work on my stereo just fine, but when i plug into my computer its like i am listening to half of a song, my other headphones that i have work fine on the same computer. Any ideas ?