Problem with itunes can anyone have any suggestions

I dont know if anyone has had the same problem, but i downloaded the new season of its always sunny in phildelphia, then updated itunes and now the audio is crackled almost like a blown speaker, but all my other applications playback fine. it wouldnt be a big deal but ive spent about 75 dollars in itunes and have another few gigs of songs stored on there. anyone have a similar problem, or have any suggestions? i dunno if this is the place to post but figured it couldnt hurt. thanks