There's been some discussion about the SonicTap music channels here after DTV switched services (from XM to SonicTap). It's been my experience that the main problem is the inconsistancy of sound quality between some of the SonicTap channels. I'm listening to them thru my AVR as well in a remote room in the house.
If I recall, we were told that DTV is looking into the problem and some here have posted that they have heard an improvement in the sound quality compared to the early days after DTV switched services to current time.