The first time I met—or rather saw—Erin Jorgensen was almost 10 years ago, in one of those big old houses with a rotating cast of roommates. I was standing in the kitchen, talking with somefriends, when a very short, heavily tattooed redhead charged into the room, scowled fiercely, then charged back out. "Who was that?" I asked. "That's Erin," somebody answered, "she plays the marimba." "What'd you do to piss her off?" "She just... she's kinda always like that."

A year or two later, I saw her at Re-bar with a band called the French Project, which played soft, hauntingly narcotic covers of songs by Serge Gainsbourg, Prince, and others, all in French. The sight of her behind her marimba was arresting—it's a huge instrument, nearly twice as long as she is tall—and the sound was mesmerizing. Jorgensen sang in a delicate almost-whisper, the warm tones of her marimba wrapping her voice like a blanket. But there was a hint of sinister in that soft sound—a blade hidden in that blanket. It was a knockout performance, and I wondered, in the years since, why she played out so rarely.

It turns out that she didn't think she was ready yet—she was practicing obsessively, unlearning what she'd been taught while studying music at Western Washington University, and reinventing her relationship with her instrument. She switched between birch and rattan mallets, explored her grip, and even experimented with how to stand. "After I left school," she says in a recent interview, "I staked everything on playing marimba." She moved to Seattle, saved up $15,000 to buy her first instrument, and began her years-long investigation into relearning how to play it. (For the record, she laughed a lot and didn't scowl once during our conversation.)

Only in the last three months has she had what she calls her "breakthrough." She was playing her Bach cello suites—a favorite exercise of hers—when "things suddenly got way easier. It was like I could do no wrong."

Good timing. This weekend is one that Jorgensen says she's spent the last decade preparing for: her song cycle Redemption. For the show, she's teamed up with Steve Fisk, the legendary Northwest musician and producer who's helped Nirvana, Negativland, Soul Coughing, Calvin Johnson, Screaming Trees, and acres of others to find their sounds. They've been messing around in the studio, recording backing tracks and playing with sounds and tape manipulations. Jorgensen is the center of Redemption, but Fisk will join her onstage, playing keyboards, manipulating backup tracks, and "tending" (his word) to her marimba sound as it passes through an ARP synthesizer and various fuzz boxes. "Steve's great at helping me with the abstract stuff," Jorgensen says. "Like, if I say, 'Can you make that sound like hot lava?' I'm not always so good with the concrete."

Jorgensen will perform Redemption at On the Boards, where she's worked in the ticket office for the past eight years, watching experimental theater and dance companies come and go. The experience has made her allergic to the pretentiousness that sometimes surrounds performance art. "It's just not that big a deal," she says. "People say, 'Oh, art is amazing, and it's going to save people, and you're an artist, and...'—look, don't include me in that fucking club. People take themselves so fucking seriously."

Jorgensen says Redemption is abstractly autobiographical, more like a concept album than straight-up theater or a concert. The songs are dreamy—she describes one as "like coming out of anesthesia"—but the subject matter can be tough. Though she would probably reject this description as too grandiose, Redemption is about existential angst. Or, in her words, "a sort of self-help manual that you invented for yourself in order to make sense of the world."

She was raised Mormon and, like many folks who grew up in religious households, her loss of faith was a disorienting trauma that still haunts her—growing up with a schematic diagram of the cosmos in your mind and then realizing that the diagram is a fairy tale sometimes leaves a universe-sized hole in your guts. "I just want someone to tell me what to do, how it all works," Jorgensen says. "And I kept falling for things—trying to find people to tell you what to do and how to live." She hasn't returned to religion, but she's flirted with almost everything else. And she's still looking.

In one song, which sounds like a Shaker hymn, she sings: "Please Lord, please Lord, please Lord, help me get my shit together." In another song, which has a medieval chant/Machaut-like sound, Jorgensen's voice climbs to delicate, fragile, high registers as she asks someone to "tell me what I want."

Another song—which may be the single if Redemption is recorded and distributed—begins with a spare beat and Jorgensen speaking softly: "So... I put an ad on Craigslist. In the Casual Encounters section. And it read: Are you an erudite, professorial type? Are you down with Deleuze and Artaud? Are you a bona fide silver fox? I might be the girl for you." Bluesy keys kick into the background and she continues: "Are you lonely? Are you bored? Do you like foreign films? Are you lost? Do you feel like nobody understands you? Are you down to fuck? Or do you just wanna hold hands?"

The song builds in lyrical and musical intensity, with ominous strings joining in and Jorgensen speeding up her delivery: "Did you kill someone? Did you beat up your wife? Do you want to hit your girlfriend with a baseball bat? Did you rob a liquor store? Are you a total fake? Are you afraid that everyone will find out you're a total fake? Are you a masochist? Are you afraid of the dark? Are you afraid of insects? Are you afraid of dying? Do you go to church? Are you a scientist? Do you believe in ghosts? Are you into getting fucked in the ass? Do you stare at yourself in the mirror?"

The result is like what I saw at that first concert at Re-bar—virtuosic artistry put in the service of a mood that feels soft, warm, disturbing, and raw all at the same time.

"My biggest thought when we starting working on this piece was fuck art," she says. "You can tell the difference between 'look at me' and someone who's saying something. For years, people said, 'You should make a record.' But I didn't have anything to say. Now it feels honest."