Ok. So you got the sample chopping part.?
Well have you read the MANUAL? Obviously you haven't cause changing the pitch of samples is in there. I own a mpc 60 and on there you go under sample edit. You should really take a couple of hours and sit down witht the manual. Go through and try everything it says. If you don't you'll be asking alot of un-needed questions.
Then again if you have read the manual and know of the "Pitch Changing" feature ignore everything I said.
I am talking about the pitch changing feature.