Chicago singer-songwriter Owen Ashworth has left behind the border­line twee indie-pop of his best-known project, Casiotone for the Painfully Alone, but his current output as Advance Base remains modest, earnest, and even sweet. The second Advance Base album, Nephew in the Wild, which comes out this Friday on Ashworth’s own Orindal label, is a quiet record, filled with serenely luminous electric-piano melodies and gentle, sashaying percussion. But evil lurks beneath the surface. “You are the devil’s kin / The sign of the beast on your skin,” he sings on “Pamela,” a song about a young girl born to teenage parents—her father deals drugs and her mother works at Dairy Queen. “You have come to fulfill a prophecy / To level humanity / And burn everything that you see,” he tells her in a soothing baritone, backed by a tender, cycling piano melody. Two songs later, he tells the story of a murderous demonic curse in a song called “Summon Satan.”

Family factors into his songwriting more these days. Ashworth is a stay-at-home dad (Holly works outside the home), and he had to sneak scraps of time during his kids’ daily routines to record Nephew in the Wild in the basement of the two-­story suburban house his family bought last year. “I have these songs ringing in my head all day till I can put the kids to bed, make sure they’re asleep. And then I can go downstairs and try to actually play the stuff—hopefully not forget it,” he says. “God, the voice memo on phones is a life­saver. I can just run to the piano—’That idea is recorded, I won’t forget it, I can work on it in six hours.’” Ashworth played most of the instruments on the album, as he usually does, recording on the same model of Tascam cassette four-track he’s used for most of his professional career. Guest vocalists and instrumentalists (generally one per song) mostly sent in their parts via e-mail.

Ashworth kept his experiments to himself. Not even his younger brother, Gordon (an experimental musician who also plays in a black-metal band called Knelt Rote based in Portland, Oregon), knew exactly what he was up to. “We were both pretty private and independent with that stuff early on,” Gordon says. “I remember seeing keyboards and tape recorders when he went off to college. He was a huge motivator from then on—being a DIY musician, self-producer, solo performer, et cetera. It hadn’t occurred to me that you can just do all that alone.”

Ashworth first visited Chicago on a tour with Xiu Xiu in 2001, when he was still living in the Bay Area. “They drove like maniacs,” he says. “I’d be chasing them like 100 miles an hour through Iowa.” Fortunately everyone survived the trip, and he had most of a day to kill in Chicago before the show. “It was awesome just to see a totally different-­looking city,” he says. “Some nice people at the show who put me up that night—their apartment was incredible. They told me what they paid for rent, and I could not believe it. It’s like, ‘Are you kidding me? It’s so much cheaper than San Francisco. Damn, I gotta move here!’”

Part of the problem was Ashworth’s customary stage volume. “I had really damaged my hearing, and I was having crazy psychosomatic reactions to the sound where I would just get angry—like bass frequencies were just so painful that they just put me in a really bad place,” he says. “Casio­tone stopped and it was a really big relief. I was happy to not hear those songs for a while, ’cause it hurt to listen to them, physically.”

“I saw someone needed a female singer and bassist,” Weinmann says. “I looked closer and I was like, ‘That’s Owen. Owen’s looking for someone like me.’” Ashworth had been too shy to ask Weinmann directly, but she answered his Craigslist ad. “She’s like, ‘This sounds like you,’” Ashworth says. “So it was like, ‘OK, I guess we’ve gotta make music together then.’”