I've got a couple of concert DVDs and the matching CDs and while the differences are subtle, I've also noticed the DVDs sound better. At first I thought I noticed a difference because I was watching the video too, but now I'm convinced the DVDs sound better. I generally listen to the DVDs in stereo so my comparison, while not A-B testing, is in a consistent format. I find the 5.1 mixes on music DVDs overemphasize the center channel and it sounds more like a live concert in stereo. Anyway, it is interesting to note the difference of 48 and 44.1 Hz for DVDs vs CDs. If that is the sole reason for what I hear maybe my middle-aged ears aren't so bad!