Discovering the bass, says Esperanza Spalding, was like “waking up and realizing you’re in love with a co-worker.” Although she moved to upright bass at the tender age of 15, the 27-year-old winner of Best New Artist at last year’s Grammys was already a classical concertmaster with 10 years of violin study and performance experience in her hometown of Portland, Oregon.

Switching to bass carried a slightly scandalous whiff in Spalding’s previous circles, but it didn’t matter—the appeal of jazz greats like Slam Stewart, Scott LaFaro, and Leroy Vinnegar had won heart. Indeed, even more than her prodigious talent, heart—her ability to “transmit a certain kind of personal vision and energy that is all her own”—is what Pat Metheny once described as Spalding’s “X factor.”

That certainly extends to her bass playing. As demonstrated on her second album, 2010’s Chamber Music Society, whether she’s playing a 7/8 or 3/4 upright double-bass, Spalding shows a technical command that’s as at home with the colors of Bartók and Webern as it is with the ghost notes and broad swaths of sound that Paul Chambers laid down on “Kind of Blue.” And then there’s her fretless electric work, which has an energy and phrasing reminiscent of Jaco Pastorius on “Teen Town” and “Come On, Come Over,” with a loaded lower-mid attack and heavily syncopated lines that suggest the middle ground between popping and rest-stroke.

Spalding—a mix of African American, Welsh, Latin, and Native American ancestry— is both lovely and instantly endearing. She’s as likely to express herself humbly as she is to be firm about her many strengths and her point of view. That combination is part of what makes her latest album, Radio Music Society, such a compelling hybrid and such an arresting listen. Fusing Afro- Cuban, bop, chamber music, jazz vocalese, and R&B with the dizzying chanteuse streak of her elastic vocals, the album is shot through with savvy lyrics that take on real-world subjects like racial pride and identity (“Black Gold”), the nature of friendship (“Cinnamon Tree”), and the price of war (“Vague Suspicions”). And then there’s the fact that she sings in perfect Portuguese.

If all that sounds improbably mature and totally kick-ass for someone still in their mid-20s, well, it is. Still, given that Spalding is the first jazz artist ever to win a Grammy for Best New Artist—and the youngest instructor ever hired by her alma mater, Berklee College of Music—it does help cement the less-than-vague suspicion that Spalding is something of a smoldering cross between a Jaco Pastorius and an Adele.

You began on the violin and upright before picking up electric bass. How does the one inform the other—what’s the hand-off?
Functionally, there are a lot of things that translate across the two, but the situations I’ve played electric in are so distinctly electric. I wouldn’t have tried to do that music on upright, and vice versa, so it’s hard to tell. I will say that things that are second nature for me on upright, I really need to think about on electric.

Fretless bass is a very difficult instrument to play well—you almost need experience with an upright to do it.
Well, I play fretless partly because frets defy my capacity to understand. Never having played a fretted instrument, the frets just… wow—I don’t know where to begin on a fretted instrument! With a guitar, I’m down with that. I get it: For chords, it helps you stay in the right place. But on the bass, with melodic movement and lines, it really trips me up.

The Fender Jaco Pastorius Jazz bass appears to be a good fit for Esperanza Spalding, whose chops have been compared to the legendary Jaco. Photo By Carlos Pericas, Courtesy of Montuno

Why?
It’s a whole different philosophy of being in tune. If you grow up playing violin, everything is about how you get to the right note in time. Then, if you land on the wrong note, how do you quickly adjust? All these things really revolve around intonation. Intonation becomes about distance and time—how much time do I need to get a particular distance across the fingerboard? And your ear guides so much of what you do when you’re playing a fretless instrument: So much depends on being able to quickly hear how close you are to the pitch.

Which instruments are you mostly playing these days?
For electrics, I’m playing a Fender Jaco Pastorius Jazz bass and a Godin A5 Semi- Acoustic 5-string, which has an L.R. Baggs undersaddle ribbon transducer. The Godin is really cool—it just sounds beautiful. It was different for them, and different for me, so they encouraged me to experiment with it. For uprights, I play a 7/8 double bass. It’s the one bass I’ve always used. Luthiers can’t come to a consensus on who made it or when, but evidently it was an orchestra bass for years until the owner died and the family sold it. It’s just really alive and really open—super resonant. But I don’t travel with it. On the road, I just ask for a 7/8 or 3/4 bass, hope it’s cool, and go for it.