The 23rd Outsound New Music Summit fills Finnish Hall at 1970 Chestnut St this weekend — four programs of experimental and improvised music, tickets $16 to $25 — in a Berkeley meeting hall Finnish immigrants built by hand in 1932.

On the 1900 block of Chestnut Street in West Berkeley, behind the plain stucco face of a building most drivers pass without a glance, the weekend of August 1 sounds like nothing else in the Bay Area: a saxophone bending toward the edge of its register, two papermakers working a screen as part of the ensemble, and, somewhere in the program, what the organizers cheerfully bill as "harsh noise."

The room is Finnish Hall, 1970 Chestnut St, and it is hosting the 23rd Outsound New Music Summit — four programs running Friday through Sunday, tickets $16 to $25 a show. The lineup, per SFGATE's listing drawn from Bay City News, spans "experimental pop to free improvisation to microtonal composition to experimental electronics to harsh noise." Friday's "Fusion vs Fission" pairs saxophonist Sam Morrison with Farallon, a trio of bassist Keith Waters, keyboardist Ian McArdle and drummer Shawn Myers. Saturday's afternoon "Avant Matinee" includes Gino Robair's Radical Divination — a structured improvisation scored for two papermakers and five musicians — and Normalways, a set featuring the guitarist Fred Frith. Two more programs, "The Art of Rocks II" and "Mountains of Sound," fill Saturday night and Sunday.

The venue is the quieter story. Finnish immigrants laid the hall's cornerstone on October 9, 1932, building much of it with member labor on land donated by a local manufacturer, Walter Mork, and opened it with a three-day festival that ran from December 30 into New Year's Day 1933. It has served Berkeley Finnish Lodge 21, founded in 1911, ever since, and is now stewarded by the Berkeley Finnish Heritage Society. It is a working room, not a monument: in June it drew a crowd for a health coach's attempt at a pushup record on the same floor these musicians will fill this weekend.

Outsound Presents, the nonprofit behind the summit, was founded in 2000 by saxophonist Rent Romus and has co-presented the event with KFJC 89.7 FM every summer since 2002. Walk past 1970 Chestnut this weekend and the marquee gives nothing away. The sound does — free parking out front, a socialist meeting hall's doors open, and microtonal composition leaking onto the sidewalk.