Jay-Z may have declared AutoTune dead, but Mariah Carey just revived it. On the debut single from her 12th studio album ("Memoirs of an Imperfect Angel," due Aug. 25 on Island Def Jam), the singer who needs no vocal manipulation uses the effect with startling success. The key is making it look easy. Along with the-Dream and C. "Tricky" Stewart, Carey has crafted a gem of a diss record that coasts, even over its sputtering moans and synth jabs. One questionable Windex analogy aside, her lyrical boasts are biting and funny, and the syrupy lightness of her vocals is tailor-made for the ribbing she gives her mystery pursuant (reportedly Eminem). Though some lament Carey trading in her sky-high notes and ballads for a more constrained, R&B-friendly range, the singer has clearly found a new comfort zone that could very well produce her 19th No. 1 hit.