Only one thing is keeping the Charlie Hunter Trio’s new Let the Bells Ring On from being named one of the best jazz-vocal releases of 2015: the band lacks a singer.

That’s sometimes hard to tell, though, for there are few more human-sounding instrumentalists than trombonist Curtis Fowlkes, who smears bluesy moans and ecstatic cries over the intricate but deeply funky rhythms of Bobby Previte’s drums and Hunter’s seven-string bass/guitar hybrid. It’s probably not going too far to call Fowlkes the Aretha Franklin of his instrument, for he’s similarly capable of deploying monstrous chops in the service of deep feeling.

Kudos to Hunter for casting this underappreciated musician as the star of his new band—not that the guitarist or the drummer is in any way subordinate.

“I’m glad you hear that, because that’s exactly what I was thinking,” says the friendly but laconic bandleader, checking in from a Santa Cruz, California, tour stop. “It’s all about his sensibility and the way he approaches his instrument. Of course, if I’d wanted to do something that was, like, über-slick and polished and super-techie, I would have gotten different people, but I wanted to do something that had a deeper narrative of experience and soul and R&B and the blues but that also had that improvisational and creative aspect as well. That’s why Bobby and Curtis are doing it.”

The 48-year-old Hunter confides that he had another motive for asking the 65-year-old trombonist and 64-year-old drummer to complete his “improvising R&B group”. “If you want the sound to have the sen­sibility of people who grew up when Bobby and Curtis grew up, you need to get people like that to begin with,” he says, laughing.

There’s a paradox to what Hunter himself is doing, however. Compared to the innovative musician’s early Blue Note albums, the self-released Let the Bells Ring On is relatively straightforward and far more raw—the reverse of how musical evolution is supposed to work. For Hunter, this increasingly emotional approach has to do with his deeper understanding of his self-invented instrument, which pairs the lower three strings of an electric bass with the middle four of a guitar.

“Ultimately, you’ve got to think like a drummer more than anything else,” he explains. “If you think somewhere in between a drummer and, you know, Blind Blake or Mississippi John Hurt, then you’ll be able to really do it. But if you think ‘Oh, this bass part has to be this and the guitar part has to be this,’ then it’s not always going to work, because you’re going to be doing too many things that don’t really fit together, rhythmically. Whatever magic there is happens in the counterpoint—the interdependence between the bass part and the guitar part.”

There’s another reason, too, why Hunter’s sounding bluesier than ever. “In the early times,” he says, “I wanted everyone to accept me as a jazz musician. That was really important to me—and it’s just something that’s not important to me anymore. So maybe I’m going back to my roots!”

The Charlie Hunter Trio plays the BlueShore Financial Centre for the Performing Arts at Capilano University on Saturday (December 12) .