In “Twenty Feet From Stardom,” back-up singers step out of the shadows into the spotlight. It’s an illuminating, if not totally satisfactory, look at their lives on and off stage.

The Morgan Neville-directed documentary, which premiered at Sundance this January and opens in theaters June 14, takes a look at the history of the modern back-up singer and what it is like to live life in proximity of fame.

Just like the underscore in a movie, great backing vocals are often integral to the finished product, but the listener’s mind doesn’t consciously register them until they are stripped away and emptiness remains. Think about Lou Reed’s “Walk On The Wild Side” and how it would sound without the “Doo do doo, doo do doo doo do doo,” or the wailing refrain of “rape, murder, it’s just a shot away” during The Rolling Stones’  “Gimme Shelter”  or “Hit The Road Jack” by Ray Charles.

In the late ‘50s/early ‘60s, as rock and roll blossomed, back-up singers transitioned from the polite, demure vocals sung by bland white girls to the gritty, full-throated singing made famous on Phil Spector’s productions. 

The story really starts with Darlene Love, lead singer of the Blossoms, and one of the all time great cautionary tales in music. Love was repeatedly screwed over by Spector, who would use her vocals, most notably on “He’s A Rebel,” but credit the song to his latest girl group (in that case, The Crystals), who would then lip sync the song. She could never get out from under his thumb. She eventually working as a maid, until in a Cinderella moment, she was cleaning a house when her signature song,  “Christmas (Baby Please Come Home),” came on the radio and she knew she had to go back to singing even if it broke her heart again. She was inducted into the Rock & Roll Hall of Fame in 2011, a grand acknowledgement of her accomplishments that had been long denied.

That lineage goes through other greats such as Merry Clayton, Claudia Lennear, Lisa Fischer and several others up to Judith Hill, a contestant on “The Voice” this season. Hill sang back up for Michael Jackson on the ill-fated “This Is It” tour and became a break-out star after singing at his memorial service. Eager to make it as a lead singer, Hill’s efforts to transition from the background to the foreground, in a story whose ending has yet to be written, frame much of the film.

If history serves as an example, Hill has a hard row to hoe. Few make it to the front lines with any great success, in part because they may possess great voices,  but they don’t play instruments or write their own songs and aren’t self-contained artists.  Sheryl Crow and Luther Vandross are the notable exceptions in the film who went from support to main attraction. While there’s no footage of Crow singing back-up for Michael Jackson with hair as high as heaven, there is magnificent film of Vandross singing backing vocals for David Bowie on “Young Americans” in 1973 as well as footage of Vandross, then a star, working with his backing vocalists: his nebulous instruction to them: “Can you give me more air?”

 But for the most part, these singers either don’t want the pressure of carrying the lead role and everything that comes with it, such as the responsibility of being a boss. Or they tried and failed, such as Tata Vega, who now tours with Elton John, or Lisa Fischer, whose excellent solo album received rave reviews and a Grammy, but she was never able to follow up. Instead of being a star of her own, she retreated to being a superstar among backing vocalists. For the last 20 years, she’s toured with The Rolling Stones.

As much as the documentary is about singing, it’s also about race and gender.  The vast majority of the back-up singers in the film, as in real life, are African American and they learned to harmonize by singing in church choirs.  Clayton talks about the conflict, as a black woman, of singing backing vocals on Lynyrd Skynyd’s seminal southern anthem, “Sweet Home Alabama.” However, she brings up the very nuanced (so nuanced that most folks missed it) “boo, boo, boos” that follow the line  “In Birmingham, they love the governor,” as a sign that the song is actually anti-racist. There’s unmined gold there in not developing the race issues further, especially for the singers in the ‘60s as the civil rights movement was coming to the fore.

Additionally, the overwhelming number are also female and that phenomenon goes unquestioned. To be sure, there are a few of male backing vocalists —the documentary includes David Lasley, who sings with James Taylor, but not the astounding Arthur McCuller (he’s the powerhouse voice you hear at the end of “Shower The People”). Why is that?  Are women’s voices better suited for backing vocals? Are men not willing to take a backseat and prefer to be the lead?

What’s missing from the film is the actual process. The backing vocalists talk about “the blend,” the magical moment when all their voices mesh to create something greater than the individual parts, but we rarely  see background singers working out their parts, showing us how it’s done. There are scant footage of  a producer or artist giving direction, but the movie focuses way more on the love of singing  than the nuts and bolts.

Furthermore, instead of hearing major artists like Bruce  Springsteen, Sting and Stevie Wonder talk about the role of backing vocalists, it would have been far more instructive—and entertaining—to have one of them break down a tune and explain how and why they decided to add backing vocals.  There is one scene with Sting rehearsing with Fischer on “Hounds Of Winter” and encouraging her to vamp and then the film cuts to her wailing on the song in concert as Sting totally cedes the spotlight to her.  The film would have been a much richer experience with more behind-the-curtain scenes such as that.

While it sounds like I didn’t like the film, I did, but it left me wanting because there’s so much potential in the topic.

Many of the singers are still patching together careers, going from song to song as hired guns. There’s a fun segment where the Waters Family talks about the odd jobs they’ve done, including vocalizing birds in “Avatar,” or African chanting in “The Lion King.”  But others tired of the road or with too many obligations to tend to have switched to more stable careers. For example,  Lennear has  taught Spanish for the last 15 years. “I never said it wasn’t for me,” she says of singing, still slightly heartbroken that she is no longer on stage, even if the spotlight was never on her.