I bought a Presonus Audiobox 44VSL, I am trying to use it through garageband to begin with since i am familiar with is, while i familiarize myself with the Studio One 3 software. I can't get playback through the headphones that are plugged into Audiobox. I can hear my microphone, but can't get playback of backing audio track. I am using a MAC. i have changed output and input to 44VSL. Still nothing.