Raphael Saadiq’s retro soul homage is almost too expertly calibrated. Cases in point: “Heart Attack,” which riffs on the driving tempo of Sly and the Family Stone’s “Dance to the Music”; or “Day Dreams” and its shuffling Bo Diddley backbeat; or the title track’s LittleWalterinspired harmonica. Still, Stone Rollin’s rhythm-and-blues revival can’t obscure Saadiq’s songwriting talents. On the redemptive spiritual “Go to Hell,” he sings, “There are channels in the valley, take me upstream” amid a gospel chorus and string arrangement worthy of Isaac Hayes. It’s an apt metaphor for a virtuoso stylist whose finest flourishes lie in the details.