For more than 20 years Brendan Burke has been content to live in the background of Chicago’s music scene, playing drums for heavy proto-grungers God’s Acre, the country band Freakwater, and the garagey Waste Kings. Burke eventually migrated to the other side of the studio glass, engineering albums by New Zealand post-rock guitarist Roy Montgomery and free-jazz musician Ken Vandermark (a fellow former Waste King). Burke is the sole responsible party for a new project, Interbellum, but his relative anonymity will probably remain intact. Burke recorded, mixed, and edited his debut album, Over All of Spain the Sky Is Clear, and plays piano extensively on every song, but the record, filled with sprawling but sparse instrumentals, is the musical equivalent of a fugue state. In addition to ivory-tickling, Burke manipulates the songs electronically—extending and warping notes, adding samples of half-heard murmurs, radio static, vinyl pops, and industrial thrum. He gets some help from cellist Fred Lonberg-Holm, who’s played with John Zorn, Peter Brötzmann, and Wilco. Though the Spartan mix of cello, piano, and samples is somber, the album’s pleasant tone and general lack of dissonance keeps the album (and the listener) from drifting into a barbituate haze. Lonberg-Holm is an amazing cellist, skillfully shifting from melodic passages to minimalist drones; he works well with Burke’s piano, and though the songs are expansive (“The Life and Death of Anne Zimmerman” is more than 22 minutes long), his style is deliberate and focused. The album is a digital-only release from Flingo Sound System (FSS), a new label run by Bruce Adams, whose old label Kranky helped introduce experimental drone music to many indie rockers during the ’90s. Over All of Spain the Sky Is Clear is downloadlble only in its entirety, and an immersive approach to Interbellum’s music makes sense—though the individual songs are often indistinguishable from one another, they work well heard as a whole. (Besides, Burke has great song titles: “6EQUJ5” comes from a revelatory code sequence picked up by the ET-seeking Big Ear Radio Observatory, and “Moitessier Turns Back” references the French yachtsman’s abandonment of his attempt to circumnavigate the globe alone.) Interbellum’s music avoids pat resolutions and conventional melodies, and it’s probably best heard in the dead of winter. Like the best experimental music, Interbellum balances entertainment with aggravation, both demanding and rewarding patience from the listener. With this instrumental epic, Burke has sublimated his ego and found his voice at the same time.