G turns, and pauses a beat. “Uh… Underappreciated, in general.” From these first 10 seconds of Lane’s new documentary about the saxophonist — and the startling backlashes he’s provoked throughout his 40-year career — you know you’re in for a revisionist joyride that’s one of the most entertaining nonfiction efforts in recent years. With Lane’s laughter, just off-camera, to G’s response, it’s apparent right away this won’t be an objective biographical account, her subject held at some artificial remove, but instead, like Lane’s other films (“Nuts!,” “Hail Satan?”), an impressionist reverie of how the material before you makes you feel. And Kenny G’s music has inspired a lot of feelings indeed. For his fans — and there are many, as the 52.4 million records he’s certified to have sold testify, putting him ahead of Bob Seger, Bob Marley, Kiss, and Aretha Franklin in sales — his music is moving and inspirational, whether providing the soundtrack to office work or walking down the aisle. To his detractors, he’s a usurper to the legacy of jazz, an artistically bankrupt hack who only has his sales going for him. Lane — whose collage-like sensibilities in “Our Nixon” and “The Pain of Others,” and exhaustive research skills, always result in the artful presentation of found footage — shows clips of radio hosts decrying G, and even one angry youth appearing to blast a G album with an AR-15.

Indeed, G is as much an heir to the legacy of “Disco Demolition Night” in the rancor he provokes as he is to any specific jazz tradition. But part of what makes “Listening to Kenny G” so fascinating is how it shows that there really hasn’t been much critical thought applied toward G at all, only lizard-brain reactions. There is no Kenny G biographer to call upon as a talking head and probably never will be. The commentators who are here alternate between not knowing at all what to say or rattling off their own obviously pre-scripted talking points that aim not to generate discussion so much as shut it down. The New York Times’ Ben Ratliff suggests he first heard G’s music while waiting around at the dentist’s office or at a bank and “associated it with a corporate attempt at soothing my nerves.” PopMatters’ Will Layman says, much like Wynton Marsalis in other documentaries, that jazz is a conversation, where one performer exists in dialogue with another. Therefore G, whose solos float like a bath toy on top of a bubbly bed of musical water, isn’t engaging in discourse at all: “It isn’t sex, it’s masturbation.” Lane set out to make a documentary about the nature of taste, and she’s accomplished that with panache. Her introduction of her talking head commentators is not to use them as talking heads at all but to train her camera on their faces as they listen to G’s 1986 breakout hit “Songbird.” If some of the grimaces that follow seem performative — as with many of the anti-G stances — there seems to be some genuine engagement with that song, and the others she then plays, as if the talking heads are really attempting to hear the songs, not just what they think they hear. Even Layman ultimately admits one of the songs is perfectly fine.

G is representative of a kind of mass culture that no longer exists, except for the odd Marvel film. His ubiquity was reason unto itself to oppose him. There’s nothing inherent in his music to provoke a visceral response: jazz purists love to carefully maintain the canon, and for them, his rejection of improvisation was disqualifying, as well as his use of the studio to edit his performances, but he undoubtedly created a distinctive sound, one that uses mixing techniques to make his soprano sax as emotive as the human voice. When you hear Kenny G, you know you’re hearing Kenny G. It’s the distinctiveness of his sound that’s so vexing. At one time, a default pose for the cultural commentariat was to be skeptical of such a paragon of mass culture. Now, if you don’t like the Marvel films, it’s heavily implied there’s something wrong with you. The wheel has turned. And Kenny G has savvily leveraged his “so lame he’s cool” persona for the social media age. The 65-year-old has unexpectedly become an “internet boyfriend” with his cringe chic. Not that he doesn’t deserve that title. Lane’s film spends the most time one on one with G, and he’s an absolute delight: an obvious hard worker, funny, self-deprecating, a purveyor of everything you’d want from an interviewee. “Am I animated enough?” he asks Lane at one point, G trying to assess if the footage being taken of him is working (and obviously caring a lot that it does work). “Or am I too animated?” “Listening to Kenny G” is a documentary counterpart to Carl Wilson’s seminal 2007 book “Let’s Talk About Love: Why Other People Have Such Bad Taste,” which examines the phenomenon of Celine Dion. Both illustrate what used to be the critical role of professing love or hate for something in one’s identity formation. Now, all too often, it’s the reverse: one’s identity determines whether they’ll love or hate something. “Listening to Kenny G” is a quiet elegy for the act of arguing over art on its own terms. How exciting to have a discussion over whether a work of art is merely good or bad, without bringing high-handed, groupthink-encouraging moralism into the discussion. No, you’re not a bad person if you don’t like Marvel. You’re not a bad person if you like Kenny G either.

Grade: A

“Listening to Kenny G” premiered at the Toronto International Film Festival and will air on HBO later this fall. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.