Common attends the 87th Annual Academy Awards at Hollywood & Highland Center on Feb. 22, 2015 in Hollywood, Calif.

Common attends the 87th Annual Academy Awards at Hollywood & Highland Center on Feb. 22, 2015 in Hollywood, Calif.

Christopher Polk/Getty Images

“I'm a Motown baby, a jazz baby—a music baby,” Regina Carter told the crowd at the Detroit Jazz Festival last Sunday, a hometown hero in the midst of one of the most star-studded jazz line-ups of the festival season (Sept. 1 to 4).

The jazz violinist tapped into one of the prevailing themes of the annual gathering, during which hundreds of thousands of people replace the cars of Motor City’s downtown for four days of free musical healing: Jazz is just one name for the city’s native musical language, one that encompasses all corners of soul, blues, hip-hop, and electronic music. While the festival’s line-up featured some of jazz’s biggest names -- Herbie Hancock, Stanley Clarke, Esperanza Spalding, Wayne Shorter, Kamasi Washington -- the resulting music still, somehow, felt uniquely Detroit.

Part of that, of course, was thanks to the local musicians who tapped into the city’s omnivorous taste in music. Carter paid tribute to Ella Fitzgerald during her set with a series of straightforward, yet invigorating takes on some of the legend’s B-sides -- she drew impressive crowd participation during a mash-up of the standard “Undecided” with “Don't Stop the Groove,” a cut from Detroit jazz-funk group The Lyman Woodard Organization, and offered one of the festival’s most generous, spiritual solos on “I’ll Never Be Free.”

Another local hero, Karriem Riggins (whose production credits include Kanye West and Erykah Badu), joined by legendary MC Common and pianist/producer Robert Glasper, spearheaded what functionally became a tribute to late Detroit producer J. Dilla, whose signature head-nodding, lyrical, laidback beats have spawned their own jazz subgenre (of which Glasper is the de facto leader). Together, they provided perfect last-weekend-of-summer ambience while offering concrete evidence of the city’s quiet but omnipresent stake in contemporary jazz.

As important was the audience’s willingness to engage with the music: The festival’s definition of jazz is orthodox compared to others that claim the genre, but despite the fact that it was all free, the crowds were as rapt for Riggins’ groovy set as they were during Wayne Shorter’s celestial explorations Sunday night, alongside Esperanza Spalding, Terri Lyne Carrington and Leo Genovese. It was jazz very nearly at its most abstract, as the group went back and forth via the highest level of music conversation, Spalding singing Schoenberg-esque lines as Shorter responded with the visceral force of a man a quarter of his age (he just turned 84). During a set that one would expect to hear in a basement in New York, an amphitheater full of people sat quietly and attentively, maybe munching on an elephant ear from the stand just behind the seats. It was the perfect example of bringing jazz to the people.

The democratization of jazz -- bringing a music that became elitist somewhere along the way back to its roots, giving a voice to people that wouldn’t otherwise have one -- is a sentiment that’s often discussed, but rarely executed as well as it is in Detroit. The festival is probably the most important one in America for encouraging new audiences, simply because it is so incredibly accessible.

And even with the heavy investment required to bring the genre’s stars out for free shows, the festival still goes out of its way to make it easy for younger fans to get involved. Students figure heavily in the lineup, and this year, donors were given free VIP passes that were only applicable to those 25 or younger. The proof that these sorts of initiatives work was in the playing: a composition called “Smart Blues,” from the trumpet player for the Wayne State University All Star Youth Ensemble. It was classic, swinging, and best of all, it inspired the audience to whoop and cheer like they were hearing the second coming of Miles himself.