In his fourth film as director (and his first documentary, billed as a “musical adventure”), John Turturro plays an amateur ethnomusicologist/corny travel guide, popping up throughout this scattershot sampler of the sounds of Naples to inform us that song is a “form of emotional transportation for many people.” That predilection for the trite often extends to the musical numbers Turturro stages, especially the one he appears in—”Caravan Petrol,” a desert-set ’60s cover performed by the one-named Italian entertainer Fiorello, which features the director’s hip-wiggling. Passione works best when Turturro tamps down his impulse to enhance the performances with florid narratives and focuses only on the singer and the song. Tunisian immigrant M’Barka Ben Taleb’s spin on “O Sole Mio” showcases rich pan-Mediterranean influences; her ululation punctuates a rendition of “Tammurriata Nera” sung with Peppe Barra. Sometimes a few more facts or history lessons would be nice: Three companionable elderly gentlemen, identified as the Esposito brothers, compare legendary Neapolitan tenors Fernando de Lucia and Enrico Caruso—a engaging disquisition cut short for another of Turturro’s musical fantasias.