The Music Choice channels on DirecTV are indeed a lower volume then the rest of the channels, and some of the MC channels are louder then others. Toggling between Music Choice on cable and Music Choice on DirecTV is a night and day difference. On cable, they are louder, more even volume, better stereo separation and much better matrixing/pro logic effect or whatever you want to call it from the rear channels. I have both my cable box and DirecTV box connected to an A/V Receiver via HDMI, with no difference in settings between the two inputs on a 7.1 setup. Kind of reminds me when DirecTV first switched from Music Choice to XM. Same thing, the volume levels on the XM channels were all over the place, but typically lower then normal channels.
From what I can tell in the limited playing around I've done, all of the MC channels that are on both cable and DirecTV and not in sync. There usually about a 1 song difference in either direction. Some times cable is ahead by a song, some times D* is ahead by a song.
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