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“Streetlight Harmonies” is a short, brisk documentary that takes us from Gospel close harmony singing as it morphed into pop music, covering The Inkspots through doo wop, Motown and The Beach Boys to En Vogue and *NSYNC.

Built on fresh interviews, some archival performance footage, stills and survivor anecdotes, director Brent Wilson — a veteran of *NSYNC music videos and creator of the most recent Brian Wilson (The Beach Boys) documentary — makes a case for a less heralded assortment of the founding mothers and fathers of rock’n roll, R & B and hip hop.

Singers such as “Little” Anthony Gourdine (Little Anthony and the Imperials), La La Brooks (The Crystals), Al Jardine (The Beach Boys) and Lance Bass (*NSYNC) walk us through the history — ancient and recent, when Gospel drifted over into the 1930s and ’40s pop of The Mills Brothers, The Ink Spots and many others and set the stage for “inner city” music to pop up from kids who couldn’t play an instrument, but who could harmonize and “get the attention of the girls” standing under street lights all over New York and Philly.

Charlie Thomas of The Drifters remembers nights when his budding group would be on one corner of Eighth Ave. in Brooklyn, and “there’d be a different group on every other corner,” all of them singing — some of them canny enough to know where singers, songwriters and producers lived, singing under their windows.

The Coasters, The Orioles, The Clovers and others got their starts just like that.

A film chapter titled “The Big Bang” recalls the genre’s breakout moment. Frankie Lymon, all of 14, and an integrated backing quartet of friends, The Teenagers, blew up with “Why Do Fools Fall in Love?” in the spring of 1956.

A legion of imitators followed — African American groups, then Italian American ones like Dion & the Belmonts, girl groups (The Crystals) by the dozen.

Dick Clark “Bandstand” barn-storming bus tours, Motown, Phil Specter’s “Wall of Sound, all smothered by The British Invasion, then brought back by Sha Na Na (Jon “Bowzer” Bauman appears), who were at Woodstock years before “American Graffiti” tapped into the late ’50s nostalgia.

The role such acts and their tours had in integrating segregated America is touched on, along with the ebb and flow of such music within the mainstream, fading away only to come back with a vengeance every dozen years or so.

En Vogue and *NSYNC members chat about the primal appeal of voices in close harmony, with Lance Bass noting “that there’ll always be a place for boys singing harmony as long as there are teenage girls.”

K-Pop stars BTS, and their forebears, Britain’s One Direction, bear that out.

Sure, it’s a surface gloss treatment of the subject, mentioning the racism groups encountered, the financial exploitation rampant back then (and on through *NSYNC).

But “Streetlight Harmonies” is valuable in rounding up a lot of the first and second generation stars and getting their memories on film before they die off. A few have passed since the making of the film.

Stories about how the music migrated from the street corners to the hallways of apartment buildings, and then “into the subways, where we sounded even better” and how the groups allied with Brill Building songwriters to conquer the world would have been lost had Wilson and his crew not gotten their testimonials about making those harmonies by streetlight on film.

MPAA Rating: unrated

Cast:  La La Brooks, Charlie Thomas, Lamont Dozier, Barbara Jean English, Ron Dante, Jon Bauman, Wally Roker, Brian Wilson, Al Jardine and

Credits: Directed by Brent Wilson, screenplay by George Bellias, Brent Wilson. A Gravitas Ventures release.

Running time: 1:24