UFC Audio

A few weeks ago i downloaded the ufc demo and played it and for some reason the only thing i could here when i was in a match was background noise crowd/trainers i could not here the commentators or bruce buffer but i guess i could here buffer's voice very faintly like an echo, but i didnt worry about this because i figured hey its just a demo. Now a couple days ago i get my pre-ordered copy and its doing the same exact thing and even in the career mode i feel like i should be able to hear the people talking in the cut scenes. I have re-installed the game 3 time's and this problem is really %#$@@#% me off, please please please please i need to know how to fix this.