Martin Shore’s valentine to Memphis musical history is the second documentary I’ve seen this week that’s bracketed by scenes of an empty chair being sat in and later vacated by a narrator. (The other is Second Opinion.) Directors, cut that out; just get to the good stuff, especially when there’s more of it than time allows. Here the narrator is Terrence Howard, whose achingly earnest listen-up-kids intro seems superfluous given a subsequent rush of so many soul-drenched and contagiously joyful tunes. It’s easy to see and hear why this music has cut across lines of race, gender, generation, and geography, enduring in part by buoying spirits during moments of otherwise completely spirit-crushing American social history. Shore’s is a torch-passing project, a chronicle of sessions for a compilation album, on which veteran Stax and Hi Records journeymen collaborate with rappers, school kids, and, for old times’ sake, each other. Since shooting, some of them have died, but clearly the Memphis and Mississippi Delta mythologies never will. There’s a lot of love in this sentimental family album, if also a familiar manner of music-doc restlessness, with shots interrupting other shots, songs interrupting other songs, and structure going periodically slack. Nitpicks notwithstanding, I’ll also say that for most of the duration of Take Me to the River my head was swaying, my heart was in my throat, and tears were in my eyes.