"Singer-songwriter" is such an open-ended term. It can stretch to accommodate musicians as diverse as '60s folk stalwart Judy Collins or contemporary oddball Devendra Banhart. So it seems fair to call rising local artist Johanna ("like the Bob Dylan song") Kunin a singer-songwriter. After all, she composes and performs her own material for voice and piano.

But Kunin is no coffeehouse canary sitting at a battered upright. She cites luminaries as diverse as jazz singer Betty Carter and Romantic composer Frédéric Chopin as discrete influences on her work. And until recently, she virtually eschewed one of the singer-songwriter's most valued tools: lyrics.

"I had some kind of beef with words," admits Kunin of her aesthetic as a music student at Cornish. "I was very adamant that my voice was an instrument, nothing more, and I really avoided them."

Instead, Kunin—who plays Thursday, April 20, at the Sunset—concentrated on improvisation. In the long run, it garnered payoffs less obvious than those of poring over old Nick Drake LPs. "[Improvisation] was great, because I was able to focus on melody, and I learned so much about just taking exactly what you hear in your head, and instantly, intuitively realizing it. Now that I've started composing my own material, I use a lot of that when I'm writing."

In turn, her sense of the voice as a purely melodic instrument shaped how she eventually incorporated words into her songs. "When I was first focusing on improvisation, it was very intellectual: 'I want to sing over this harmony,'" she recalls. "Then it turned into, 'What does this note, as opposed to that note, feel like?' What is the emotional pull of one note over another? And I think about that—not consciously, but it informs the way I place words with the melody."

Kunin has thus far issued two teasers—the spare, self-released EP Up North, and an edition of Karl Blau's Kelp Monthly audio periodical. Fans bewitched by her sparse arrangements on those discs may be pleasantly surprised by her new material, showcased on the forthcoming, Tucker Martine–produced Clouds Electric. On "Mobius Waves," tambourines, glockenspiel, and organ punctuate her reverb-drenched ivories and measured, mesmerizing vocals, while "Olos," centered around a series of repeated, four-note cells and Kunin echoing her own vocals, incorporates xylophone and puffs of woodwind.

Although Clouds Electric won't be out until later this year, fans can visit Kunin's MySpace page to sample her forays into this more layered, textured sound. "I wanted to have a big, exciting project with Tucker," she says, apropos of the full-length, "that would have all these amazing players on it, and be fully realized."

That excitement is reflected in her plans for Thursday night's show, too, which features Kunin playing with "the largest ensemble I've had to date." But she's still allowing for happy accidents. "[The set] is pretty structured and arranged, but I have a jazz background, so I like a little bit of spontaneity. I've got to have some wiggle room."