Bartok‘s String Quartet no. 4—with its antagonistic opening, bad-dreamish slow movement, and aggressive fury—is possibly his gnarliest, and since the Seattle Chamber Music Society treats music this uncompromising gingerly, it’s a gratifying surprise to see it among the programming for their winter festival. Three of this weekend’s four main concerts (all but Saturday’s) are preceded by less-formal recitals an hour earlier; each of these will feature one of Brahms’ three quartets. In addition, there’s a family concert—the musical fairy tale The Bremen Town Musicians, 11 a.m. Saturday ($10)–and KUOW host Dave Beck chats with SCMS artistic director/violinist James Ehnes on Thursday at noon.

Thursday, 7:30 p.m. Shostakovich’s demure and (mostly) innocuous Quartet no. 1, plus Mozart and Schubert.

Friday, 7:30 p.m. The Bartok is cushioned by luscious pieces by two composers not known for chamber music, Mahler and Strauss, and by a Beethoven piano trio.

Saturday, 7:30 p.m. Ehnes and pianist Andrew Armstrong play Tartini, Beethoven, Paganini, and Franck.

Sunday, 1 p.m. Prokofiev’s Cello Sonata, Dvorak’s charming and homely Bagatelles, and a Brahms quintet.