scratchy sound in MacBook Pro

I've been having this scratchy sound in my speakers since the first day I got this MacBook Pro. So, I use to put headphones just to ignore it but nowadays its starting to occur in the headphones as well. What should I do? Should I ask for a new MacBook or is there anyway to fix this? I bought this laptop just to use the Logic Pro and this scratchy sound really ****** me off while I'm working on my project. And I can't change the format in audio MIDI setup from 44,100 Hz to 48,000 Hz. It doesn't move down. I can't take it anymore. No-one ever wants this kind of problems in their brand new £2000 worth laptop. Seems like lots of people are having this problem. I feel like I should've never bought this expensive worthless piece of laptop. Should I ask them for a new one? Or every MacBook Pro have the same problem?