Beginning in the late 1970s, while making the transition from background singer to phenomenal solo act, Luther Vandross shaped the sound of commercialism as much as he shaped the sound of modern American music. He recorded lucrative jingles for Juicy Fruit, Miller beer and even Gino’s pizza. During the Gino’s session, he was asked to personify a sizzling hot pie coming from the oven, and he improvised by quickly dropping his tenor into the hadal zone of his body and retrieving it, like a free diver collecting pearls.

“I could see the control room just jumping up and clapping,” he says in one of the interviews laced throughout “Luther: Never Too Much,” a new documentary by Dawn Porter (in theaters).

It was a genius stroke. He developed a signature as recognizable as Whitney Houston’s record-length notes or Mariah Carey’s fluted crystalline range. Vandross’ musical intelligence predated what is obvious in the era of TikTok: A distinct sound is worth the price of gold.

Vandross left a full, rich archive, yet there’s still an emptiness at the heart of it that manages to come through in Porter’s engrossing work. She starts her chronology with his second birth. In an interview clip early in the film, Oprah Winfrey asks Vandross when he knew he could sing. He answers that he decided to sing after seeing Dionne Warwick perform in 1963 in Brooklyn.

“I wanted to be able to affect people the way she affected me that day,” he explains. Notice how he didn’t specify a date. Notice how he knew the voice was always there. He just chose the way he wanted to use it.

In the film, a white interviewer asks Vandross, who grew up in the Alfred E. Smith Houses in Manhattan, if he was poor then. His response is earnest if not amused. “My impression of life growing up was great.” He knew something that she did not: Money is only one kind of wealth.

In her essay on Black aesthetics, “Characteristics of Negro Expression,” Zora Neale Hurston reveled in our desire to gild language, ideas, stories, gesture, clothing in resplendent layers of flamboyance. “There can never be enough of beauty, let alone too much,” she observed. Hurston wrote her oracular essay in 1934, nearly 20 years before Vandross was born, but she named a tradition that he would uphold in his own time.

Before he would perform as part of the group Luther or go out on his own, Vandross sang backup for everyone: Carly Simon, Diana Ross, Donna Summer, Chaka Khan, Bette Midler, “Sesame Street.” Porter draws a new cosmology of a freer soul and R&B sound drifting down from Philadelphia in the late ‘60s and ‘70s. Music journalist Danyel Smith describes it in the documentary as an adult Motown, a scene that wasn’t worried about matching outfits and “being in bed by midnight.”When Vandross was ready to release his own music as a solo artist, none of the record labels would touch him; he had to ask his friends, including Cissy Houston, to lend their time for free. He directs them to play a song he wrote. At first, they were taken aback by its unusual bass line. The demo session became “Never Too Much,” which the film understands as his most enduring masterpiece.

Although there’s a deep trove to pull from, Porter keeps the focus on Vandross’ live performances. His honesty and comfort onstage, along with his theatrics and exuberance, made him a legend.

Collective cultural processing has become its own genre of entertainment. Much of the work of contemporary documentaries is to reveal past pop-cultural metanarratives as apocryphal. They push us as viewers to reckon with a past that was shaped by a coterie of media organizations and anchors who were often serving their own best interests in capitalizing on the most salacious and scandalous stories. Perhaps, also, these documentaries help us practice our current media literacy.

Here, Porter makes the case that fat phobia terrorized Vandross and minimized his accomplishments. Music had its own Jim Crow, and Black artists were segregated on stages, and in record stores, by genre. Vandross refused to be diminished. He saw his eight Grammys and 40 million albums sold as momentum for the civil rights movement. But it was his public weight fluctuations that interviewers pressed him on. The media didn’t hide their fascination and repulsion at his appetite. People debated their preferences for “big Luther” or “little Luther” on television and in my high school.

The media’s relentless obsession with his weight pushed Vandross to withdraw from public view. Porter frames his reclusiveness as protection, which only made the rabid probing worse. His sexuality was scrutinized almost as much as his body; once, after a dramatic weight loss, there was a rumor that he had contracted HIV. Another time, he watched a pastor on television say a prayer after a rumor circulated that he had died. Vandross refused to entertain the violations of privacy. He owed the public nothing but “my best effort,” he said. “That’s all.”The 1988 song “Any Love,” which he described as his most autobiographical, included the lyrics “Now all you need is a chance to try any love.” Max Szadek, his assistant, interpreted that as desperation. “He wasn’t seeking love; he was seeking any love,” he tells Porter.

But Vandross always seemed to sing with faith, not fear. “I don’t consider myself unlovable,” he told an off-screen interviewer. “But I’m still waiting.”

The fulcrum of the film is heartbreak — ours, not his — that someone responsible for shaping the universal feeling of falling in love never experienced it himself. Acceptance arrived in his 2003 song “Dance With My Father,” which finds peace in growing up well loved in a home with both parents.

Vandross drifted back into the collective consciousness last summer when Solange Knowles (under the moniker of her art studio, Saint Heron) released a collection of handblown glassware. The beautiful objects were displayed in conjunction with a new installation: large screens showing a live 1989 performance of Vandross singing “A House Is Not a Home” at Wembley Stadium in England.

At Vandross’ funeral in 2005 (the singer was 54), the ever-regal Warwick was helped to the lectern to give a eulogy. The film is punctuated with interviews with her and details about their lifelong friendship and collaboration. (She first wrote the lyrics that Vandross readorned and that later inspired Knowles’ beautiful home décor.)

Warwick’s speech is brief. “His legacy will live on forever.”