When I'm using my PT rig everything sounds fine inside of PT. But when I want to route system audio through the PT hardware, I get a rather weird kind of sound. I tried SoundJam, Mint audio, iTunes, and Quicktime, and every one of them gives me this rather weird noisefloor. If a track is really low in volume like a fade in or fade out, I can hear weird digital noise and a bit of hissing until the song is at full volume, then the song masks it, but it's still there. This disappears completely when playing a song inside PT.
I know I shouldn't use system audio thru a PT rig, but the ONLY thing I want to route thru it is an audio player. When I installed PT apparently a driver was installed to get it to show up in the Sound control panel. I looked for an update for the driver but couldn't find one and I'm not sure that would help anyway.