I doubt that the DVD player is to blame, as it should be passing the digital bitstream without any alteration - something so badly out of whack that it could create an issue with the signal would show up in lots of other ways. My initial suspicion is related to either the speaker (even without damage to the tweeters, the combination of metal dome tweeters and Canadian speakers like Axiom or my old Paradigms can come across as bright in some circumstances) or how the disc is mastered, but I am not familiar enough with Norah Jones' discs to know if it could be as simple as the way the disc was mastered. The speakers in your iMac are likely to roll off a lot faster than the M80's, so it's very possible that the computer speakers wouldn't reproduce the "problem" frequencies even if it was a disc issue.

Others who are more familiar with Jones' work may be able to answer fairly readily of what you describe is typical for these two discs. Failing that, I may be able to run a little test. I just looked next to me and discovered a copy of the CD of Come Away With Me in among my wife's CD's (I think she got it from her sister at some point and decided she didn't like much). If you know of some consistent problem spots on that disc, I can toss the CD in my two-channel system (OPPO 980H and Outlaw RR2150). I usually use AV123 X-LS speakers in that system, but if I can get that close to the floor I'll finish hooking up the old Paradigm towers to the B speaker output of the 2150 and try those passages with both sets of speakers. The Paradigms and M80's are voiced rather similarly, so there's a fair chance that I could slot a disc issue.
Sitting in his den, resting a bit (stood too long trying to help with the dishes, curse this bum leg) while a certain three-year-old watches Dora behind me... Hey, you asked...