When guitarist Nels Cline, saxophonist Larry Ochs, and drummer Gerald Cleaver take the stage at Johnny Brenda's this week, they'll be spontaneously creating music in the moment - the very definition, most would say, of free jazz. But whenever Cline mentions the term in conversation, especially in regards to his own music, the term

free jazz

is audibly couched in wry, careful air quotes.

"You need to put air quotes around every so-called musical term or niche," he says with a laugh. "They're all inherently limiting or self-defeating when handled inelegantly."

It's understandable that Cline shies away from genre. He has built a career on kicking down stylistic borders and crossing unexpected wires. A veteran experimentalist, his latest album, Lovers - on Blue Note, of all things - is an adoring (if dark) tribute to classic mood music, albeit one that laces its martinis with something a bit more mood-altering. Meanwhile, on the rare occasions he's not making explosive, edge-walking music with a host of collaborators in New York City, it's probably because he's on the road with Wilco, serving as a disrupting agent for front man Jeff Tweedy's folk-pop tunes as he has for the last dozen years.

The trio with Ochs, a cofounder of the legendary Rova Saxophone Quartet, and Cleaver, a prolific drummer who has worked with a long list of forward-thinking artists, including Craig Taborn, Wadada Leo Smith, and Matthew Shipp, is a relatively new venture. They originally got together for a brief East Coast tour that brought them in January to Boot & Saddle. Their return will feature a different guitar-centric opener each night - composer/filmmaker Sarah Lipstate's solo guitar project Noveller on Thursday, Philly shredder Nick Millevoi's Desertion Trio on Sunday - while that second night holds a special treat: the addition of Sun Ra Arkestra leader Marshall Allen to the lineup.

"That's completely mind-blowing to me and something I wasn't sure was actually real," Cline says about the prospect of working with the 92-year-old Allen for the first time. "I thought it was fantasyland.

"My view of Sun Ra's importance and influence has grown as I've been able to look back over my shoulder and see the historical significance and impact of his music. It's some of the most bold and innovative and universally creative music ever made."

Despite his reluctance to slap a free-jazz label on his own music, Cline fiercely comes to the genre's defense when it's attacked from the outside. At the mention of Sun Ra's name, he revives the debate over Ken Burns' 2001 documentary Jazz, which controversially skipped over more experimental forms of the music in favor of a narrow focus on more traditional approaches, as embodied by the series' artistic director Wynton Marsalis.

"If you remember when everybody was upset by Ken Burns' jazz documentary, I was one of them," Cline says. "I was incredibly annoyed and disturbed by what I felt was an attempt to write free jazz out of jazz history. At that point, it became almost a sociopolitical, not just an aesthetic, issue for me to reinvestigate and reinvigorate myself with that music and its significance."

At its essence, though, free jazz, improvised music, or whatever you want to call it is simply a sonic conversation between freethinking artists. The Cline/Ochs/Cleaver trio represents some fairly new relationships, though Cline has listened to Ochs with Rova dating back to the 1970s and played with the ensemble in expanded lineups that explored Coltrane's most expansive and far-reaching music. Both Rova's Electric Ascension and the Celestial Septet, a combination of the Rova Quartet and the guitarist's Nels Cline Singers trio, have performed in Philadelphia.

"Larry has that free-jazz saxophone sound that was very prevalent in the early '70s, with all the resonance and power of not just the generally accepted tenor saxophone heroes like Coltrane, but also those like Pharoah Sanders and Albert Ayler that I started listening to when I was entering high school and that a lot of people don't seem to refer to as much. Larry can really bring that vocabulary to the fore in a way that I find heartwarming."

Cline had never crossed paths with Cleaver until the trio first assembled in 2015, so their collaborations still teem with the thrill of discovery. "It's been really cool and unexpected that this little entity has been born and continues," Cline says of the trio. "It's been incredibly fun."

Nels Cline/Larry Ochs/Gerald Cleaver Trio. 8 p.m. Thursday and Sunday, Johnny Brenda's, 1201 N. Frankford Ave. Tickets: $18. Information: 215-739-9684, arsnovaworkshop.org.