BOSTON CHAMBER MUSIC SOCIETY| October 16 | This esteemed consortium of chamber players, under the direction of violist Marcus Thompson, features a season devoted to one of the richest forms of chamber music, the piano quintet. The season opens with one of the least familiar, by the profound Russian composer Sofia Gubaidulina. There's also a late Mozart piano trio, Charles Loeffler's Four Poems for Mezzo-soprano, Viola, and Piano (Krista River, Roger Tapping, Mihae Lee), and Schumann's Fantasiestücke . Discounts available for students and seniors. | Sanders Theatre, 45 Quincy Street, Camberidge | $20-$53; students $12-45 | 617.349.0086 or bostonchambermusic.org.