Nina Simone was a performer first and foremost; her recordings had to translate the drama and intensity of her live presence. This tribute set finds some of her clearest heirs — Lauryn Hill, Mary J. Blige, Common — reworking her standards with love, but the results veer sharply between transcendent and tepid. Hill brings power and grace to classics like "Feeling Good" and "Black Is the Color of My True Love's Hair." Singer-songwriter Alice Smith nearly steals the show with her bewitching "I Put a Spell on You." But it's Simone's own voice on the album's closing number, "I Wish I Knew How It Would Feel to Be Free," that reminds us what, and who, we're missing.