I've being doing some similar experiments with my DAC X and my brother's computer. I ran the following comparison:- CD6 player as the transport vs. 96kHz optical digital output from computer sound card. An identical track (but different formats) was played using each setup:- conventional CD vs Linn records high bit rate download, FLAC 24bit 88.2kHz. My impression was that vocals in high bit rate track sounded more natural - the soprano's voice seemed life-like and seemed to be more separated from the orchestra. However, overall I preferred the presentation of the CD6 playing the CD - there was more warmth and the mid-range had more definition than the FLAC track. However, it was a very close call and more listening is definitely required to confirm my findings. In retrospect, a more scientific approach would have been to compare the CD format + CD transport combination to a CD track ripped to 44.1kHz + soundcard combination, both into the DAC X as a control. Very interesting experiment though. Has anyone had different experiences?