Another Item I've noticed which may help you.
No matter what I set the audio input to in the settings, I get sound. I wonder if that's a function of the thin client. Th other curious thing is whatever audio source I have selected, if I go to the mixer and move the volume control, the blue bar in driveline changes. I can only move the blue bar in driveline if I press the speaker and turn it grey, then I can change the height of the bar, but it makes no difference in the sound or in the mixer's volume position. I changed the audio input to CD, and if the bar is blue and I go the the mixer and change the CD volume, the blue bar in Driveline moves. But through all this it's really the Line In that changes the volume that I hear.