Can anyone out there actually tell the difference between say, a recording using the Pro Tools MBox Pro utilizing the internal clock, as opposed to being clocked externally to a high end Apogee AD converter? I cannot hear the difference no matter what volume or source I use (headphone or speaker). I am listening for the transients....the clarity or sharpness of a snare hit between one setup and the other. Or the lack of definition in the unclocked signal. It is not obvious. Can anyone describe how they hear the difference between the clocked and internally clocked recordings? What part of the recording would exaggerate any difference?