Robert Glasper has made his name by mapping out the connective tissue between jazz and hip-hop. (Erich Schlegel/FOR THE WASHINGTON POST)

As Robert Glasper feels out the piano during sound check, he finds a key whose frequency causes the entire sound system to buzz. It’s as if he’s trapped a hornet beneath his fingertip. He winces at the glitchy note, but keeps hitting it. Slowly, the knot in his brow loosens. His mind changes. “That’s nice, actually,” he says.

Glasper’s first and only performance at last month’s annual South By Southwest music festival is about to take place in the Elephant Room, a tiny subterranean nightspot that on this night has a line down the block. The club is crammed with fans wearing jazz goatees and Run-D.M.C. T-shirts. Glasper’s fans, clearly. The 33-year-old pianist has made his name by mapping out the connective tissue between jazz and hip-hop — an endeavor that’s come to fantastic fruition with his new album, “Black Radio.”

He folds his leather coat into a wad, sets it on top of the piano and guides his band into John Coltrane’s “A Love Supreme.” Casey Benjamin chants Coltrane’s three-word refrain through a vocoder as if reciting a sort of techno-spiritual prayer. Mark Colenburg’s drumming evokes a typewriter speaking in tongues. Glasper sits back. His chords hang in the air like fog. After certain passages, he returns to that distorted, buzzing note, transforming a technical difficulty into an exclamation point.

Eleven hours earlier, Glasper has just arrived in Austin and it’s his phone that’s buzzing with with text messages from his friends Questlove and Yasiin Bey (Glasper still calls the recently re-christened rapper Mos Def).

The screenshot on his phone is a grab of the latest Billboard hip-hop and R&B albums chart. His band, the Robert Glasper Experiment, sits at No. 4. “Whitney Houston, Young Jeezy, Jay-Z and Kanye West, Estelle, Mary J. Blige — under us,” he says, chewing on a toothpick.

“Black Radio” has topped Billboard’s jazz charts, too. But Glasper is more excited that his music is crossing over to new ears while stirring up a jazz world that he feels has been locked in stasis for decades. With cameos from rappers Bey and Lupe Fiasco, singers Erykah Badu, Bilal, Chrisette Michele, Stokley Williams of Mint Condition and others, “Black Radio” smudges the borders between hip-hop, rhythm and blues, and jazz, with Glasper’s acoustic piano playing providing the music’s unbreakable spine.

“I think I’m bringing jazz to the forefront for people who normally don’t check out jazz,” he says.“They aren’t gonna receive it if you’re playing a Charlie Parker song. But they’ll receive it if you have Erykah Badu singing.”

Glasper grew up on artists who thrived at the intersection of jazz and R&B — Miles Davis, Herbie Hancock, Gil Scott-Heron, Donald Byrd, Roy Ayers. “Those are just people who didn’t care,” he says of his pantheon.

But his mother, the late jazz vocalist Kim Yvette Glasper, was his greatest influence. Instead of leaving her only son at home with a babysitter, she brought Glasper to the nightclubs where she performed. Hearing his mother sing there and in church steered him toward the piano where he quickly learned to pick songs off the radio. It earned him entry to Houston’s High School for the Performing and Visual Arts — the same school that produced Beyonce, and the Kennedy Center’s current artistic adviser for jazz, pianist Jason Moran. After graduating, Glasper headed off to the New School for Jazz and Contemporary Music in New York, where he immediately gravitated toward R&B singer Bilal in a student jam session.

“First impression was, straight up, he could swing,” Bilal says. “He was quick-witted and he plays that way, too. He’s very witty. Very clever.”

Before long, Bilal was dragging his new friend to the Roots’ legendary jam sessions at the Wetlands nightclub in Tribeca, where Glasper made connections that would lead to collaborations with Q-Tip, Kanye West, Common, Maxwell and other hip-hop royals. Later, he’d hit the road alongside fellow jazz artists Russell Malone, Mark Whitfield and Christian McBride. To Glasper, the two worlds didn’t feel so separate.

“Hip-hop is the new jazz,” he says. “It’s a music that reflects a society. It’s a music that speaks to things going on in the era you’re in. . . . That’s what Miles was doing. He was always about being up with the times. And that’s what I’m doing. I can’t live for 1964. I wasn’t there.”

Another parallel between jazz and hip-hop’s most vital years: Each genre was driven by relentless competition. Glasper mourns that loss in jazz.

“I think everybody stopped trying to outdo each other and everybody started paying homage,” he says. “I love all my jazz masters and my elders that came before me, but I always say that people have killed the living to praise the dead. It’s like, ‘Yo, I’m here.’ ”

In addition to sounding fresh, “Black Radio” sounds assured — despite being recorded in just a few days. Glasper says only half of the songs were decided on beforehand and nearly everything you hear is a first take.

“My band is the best,” he says. “You could argue that my guys are the best on their instruments.”

They make that argument themselves at the Elephant Room, unspooling a riveting vocabulary of melodies and textures. Songs billow, then dissolve, then effortlessly twist into focus. Did anyone realize we’ve been listening to Nirvana’s “Smells Like Teen Spirit” for the past five minutes?

The faithful cheer for an encore, but the club insists on sticking to the schedule and striking the stage. Glasper grabs the microphone.

“Really?” he asks. “The next band doesn’t have a line outside.”

The Robert Glasper Experiment performs at the Warner Theatre on April 3.