More musical talent on display than in any other pic you’ll see this year. Director Morgan Neville’s masterful documentary backgrounder on the golden age of black female backup singers hits us with a tidal wave of soul, as Merry Clayton, Darlene Love, Táta Vega, Claudia Lennear, Judith Hill, Lisa Fischer, Patti Austin, and many, many more singers demonstrate why they deserve the better-late-than-never recognition. Their “bosses” admire the singers’ work, too — we hear from Stevie Wonder, Mick Jagger, Bruce Springsteen, producer Lou Adler, et al. Among the multitude of anecdotes: the story of how Ms. Clayton was called out of bed in the middle of the night to come to the recording studio to sing the powerhouse “Rape! Murder!” refrain in the Rolling Stones’ “Gimme Shelter.” Lovers of classic R&B and rock will never get tired of revisiting this movie and its bonanza of performance footage.