BORROMEO QUARTET While two other quartets are sailing through the complete Beethoven cycle this season, the Borromeo is chipping away at Bartok’s epic set of six quartets. The Second, Fourth and Sixth are scheduled for today’s performance. Oct. 18 at 1:30 p.m., $23, Isabella Stewart Gardner Museum, 617-278-5156, www.gardnermuseum.org
BOSTON SYMPHONY ORCHESTRA Ludovic Morlot, formerly a BSO assistant conductor, returns to the orchestra with a program that includes the American premiere of Augusta Read Thomas’s “Helios Choros II (Sun God Dancers)’’ along with works by Martinu and Tchaikovsky. Pianist Peter Serkin will also be on hand as the soloist in Stravinsky’s “Capriccio.’’ Oct. 20 in Symphony Hall. Meanwhile, the orchestra’s chamber players (and guest pianist Marc-Andre Hamelin) take to Jordan Hall this afternoon with works by Schulhoff, Carter, and Brahms. 617-266-1200, www.bso.org
BOSTON CHAMBER MUSIC SOCIETY It’s Schubert, Brahms, and Harbison for the season-opener under the new leadership of violist Marcus Thompson. He’s joined by Ida Levin (violin), Andrew Mark (cello), and David Deveau (piano). Oct. 18 at 7:30 p.m., $20-$50, Sanders Theatre, 617-349-0086, www.bostonchambermusic.org JEREMY EICHLER 
