It's a tad disconcerting to hear Mariah Carey's once-unrestrained voice squeezed through producer T-Pain's trademark auto-tune warble machine. "Migrate" kicks off E=MC², Carey's 11th album, and you could call it a symbolic moment: the final taming of Carey's vocal excesses in service to a song. Carey's triumphant comeback has been less about the Emancipation of Mimi than the continued Devolution of R&B, where multi-producer consortiums fuss over ringtone-sized melodies tailored for non-singers. In such an environment, the five-octave gifts that Carey once freely bestowed are no longer necessary. That's not to say E=MC² — helmed by Jermaine Dupri, Stargate, "Tricky" Stewart, and the usual cast of thousands — doesn't have its charms. On one hand, it's slick and summery — "I'm That Chick" is loopily irresistible disco; on the other, it's as dark and confessional as anything Carey has released. But it's hard not to get a little nostalgic for the old Mariah when listening to the gospel-glimpses in the closing "I Wish You Well." Critics once decried Carey's vocal acrobatics, and we got American Idol in return. Ever get the feeling you've been cheated?