The defining quality of Harris Eisenstadt’s Golden State quartet, other than its unusual instrumentation, has to be the intricacy of its leader’s compositions. Riding on the stacked architecture of Eisenstadt’s drums and the meaty thrum of Mark Dresser’s big-toned acoustic bass, bassoonist Sara Schoenbeck and flutist Nicole Mitchell create intersecting planes of melody, before twisting their lines into loose and lively counterpoint.

There are precedents for this kind of approach: on Golden State’s eponymous debut, Eisenstadt’s ballad “Sandy” bears at least a passing resemblance to the pioneering chamber jazz of Gerry Mulligan’s 1950s band with Chet Baker, while elsewhere there are echoes of the more radical pianoless quartets led by Ornette Coleman in the 1960s and Anthony Braxton in the 1970s. Mostly, though, Golden State sounds fresh, intellectually seductive, and very much like itself, which leaves Eisenstadt with an interesting challenge: how is he going to retain the band’s distinctive sound now that circumstances have forced a change in personnel?

Admittedly, the alteration is only temporary. A relative’s health crisis forced Mitchell to drop out of the Canadian tour that will bring Golden State to the TD Vancouver International Jazz Festival this weekend, but Eisenstadt reports that this has been successfully resolved, so she’ll be available for future activity. It’s also unlikely that anyone will object to her understudy, clarinetist Michael Moore. An American who’s lived in Amsterdam since 1982, he’s been a hit here with his own bands, as well as with various assemblages of Dutch jazz masters. He’s also had a long creative relationship with bassist Dresser, so it’s not like he’s new to the family—but, still, he’s a more lyrical, less heady improviser than Mitchell, and Eisenstadt intends to take full advantage of that.

“There’s a new book that we’re playing on this tour,” the drummer reports, on the line from improv impresario and former Vancouverite Cem Zafir’s Something Else! festival in Hamilton, Ontario. “I don’t know if the tunes are less contrapuntal, necessarily, but they’re a little simpler. For the Golden State record, I ended up writing some really hard music, maybe inspired by the fact that I had all these heavy readers. But with this, I just was thinking, ‘Well, we’re just going to have a quick rehearsal and start a tour, so I’m not going to bring in a bunch of 10-page tunes and hope for the best.’ ”

Eisenstadt praises Moore’s “deeply, deeply soulful and lyrical playing” and notes that this will fit well with Schoenbeck’s approach—which he says he was in love with even before the two decided to become a couple.

“She just really wears her heart on her sleeve,” the Toronto-born, Brooklyn-based percussionist says of his wife and bandmate. “Not to completely clichéify it, but I love that about her approach to improvising; she really commits. And I love the timbre of the bassoon, and how she’s really dedicated herself to expanding the possibilities of that instrument. I love working with saxophonists, but it’s a pleasure to work with an improvising bassoonist—and I wish we did more, except we’re busy raising our son.”

Harris Eisenstadt’s Golden State plays the TD Vancouver International Jazz Festival at Ironworks on Saturday (June 28). Eisenstadt also joins British pianist Alexander Hawkins and local clarinetist François Houle at Ironworks on Sunday (June 29), and at Performance Works on Tuesday (July 1).