Guitar Heaven reprises the cameo-heavy formula Carlos Santana has used since 1999’s Supernatural, only this time the celeb vocalists lay into an assortment of classic-rock covers. The performances are mostly faithful to the originals, and Chris Daughtry gives Def Leppard’s “Photograph” a credible kick. But only about half the songs get any traction — “Back in Black,” where Nas rhymes beside anonymous rock-chick vocals, sounds like a Super Bowl halftime show. The best turn is from a smaller name: India.Arie, who finds the soul in “While My Guitar Gently Weeps.” As for Santana? Smooth, as usual.