David Balakrishnan says the two ensembles that most reflect the classical tradition are the symphony orchestra and the string quartet. Balakrishnan should know. He grew up playing the violin, and has spent most of his 59 years as a musician. Plus he plays in a string quartet.

But that’s where he puts the lie to his own statement, as the San Francisco-based group he founded, Turtle Island Quartet, plays jazz, not classical music.   “It’s an approach to string quartet music that has a lot of legs,” said Balakrishnan of his group, which has been around now for nearly three decades.

That’s actually longer than Balakrishnan has been a member. He left the group he’d founded in 1993 and returned in 1997. “I was lucky enough to come back and not kill it,” he said with a laugh.

Since the Turtle Island Quartet’s inception in 1985, the one constant has been cellist Mark Summer. The other three chairs have been filled by nine other players, five alone on viola. “We sometimes refer to it as the exploding viola chair,” said Balakrishnan, referring to the similarly unlucky drum chair in the mock rock band Spinal Tap.

Balakrishnan says the integration of new members into the group typically serves as a catalyst. “It’s like a Corvette with a new engine,” he said.

In the case of TIQ, the addition of Mateusz Smoczynski on violin and Benjamin von Gutzeit on viola has not only changed the dynamic but has nearly halved the average age of the group. “They’re 29 and 33, I’m 59. That’s like my kids’ age. I envy their health and open synapses.

“We thrive on turnover,” Balakrishnan continued. The style doesn’t change, but we take a different look at the prism of jazz.”

He also notes that younger string players now see more possibilities thanks in large part to the work of he and his bandmates. “What drives a kid to break away from classical? By nature such a person is rebellious, or at least not satisfied with the status quo. How can you say, ‘You’ve never heard Hadyn like this!?’

“Jazz  has the element of improvisation. Things change every night,” he added.

Not that he in any way denigrates the classical tradition. He says the knowledge, ability and passion one has to have to bring something fresh to playing the challenging music of such acknowledged masters as Haydn, Beethoven, Brahms and Tchaikovsky demands a high level of musical ability. He just wants to be able to play and offer something different. “We respect the bona fide tradition of the (string quartet) form without breaking the rules,” Balakrishnan said.

Most string quartets don’t play the music of Jimi Hendrix, John Coltrane, or Dave Brubeck. And assuredly most of them aren’t improvising on the tunes as do typical jazz players. But that’s the niche Turtle Island has created for itself.

“When we were on Windham Hill (the label associated with so-called new age artists like George Winston), we had to shout what we were,” said Balakrishnan. Now, years later, people know and appreciate what the quartet does. And so do its members.

“It’s so much fun,” Balakrishnan enthused. “It’s like we’ve been given the keys to the candy store. We get to solo—it’s a different feeling for a string player.

“People respond to the sound. I’m lucky to still be doing something I love.”

Turtle Island Quartet performs at Corson Auditorium at Interlochen Center for the Arts on July 13. For ticket information, go to Tickets.Interlochen.org or call 231.276.7800.