I was listening to HD Radio for the first time this week and it led me to the following... Many stations now use digital files for broadcasting music. With AM or FM, the fidelity is compromised (compared to HD). But my question is: What is the 'quality' of the mp3 file that is being used by HD stations. Or for that matter, by SiriusXM? If they are just standard 128 files, then what is the point of added fidelity? Can someone on the list provide some insight into the broadcast quality of audio files on HD Radio and for SiriusXM? thanks.