Buzzing noise/sound when playing music in iTunes 11.1.3

Hi,

First of all I just wanna appologies if there's a similiar or exisiting thread on this matter.

Here it goes:

When I start Itunes with my Macbook Pro, OS X Maverick it has recently started to make a buzzing sound/noise - Kinda like a static noise. I pause the music and it continues to do so, but if I close iTunes it stops completely.
I've downloaded all the newest updates for Maverick and I've reset PRAM. Nothing seems to fix this issue.

I've also tried to switch headphones to see if the issue goes away.

Thanks!