I want to record my acoustic guitar with a 4 bar lick. I have Protools with MBOX. The thing is I want to use the recorded sample as a loop but how do I make the sound so it doesn't just chop off after i stop playing? I want to make the last bar hit on the same beat? Do I have to edit the sample or is there something that I have to do in my recording and then post production that I have to do?