Holy Trinity Church of Cambridge, MA, will present “Timeless Classics: The Music of J.S. Bach,” on Sunday, Sep. 23, at 1 p.m., in the church sanctuary (145 Brattle St., Cambridge). Featuring the Sargis Karapetyan Quartet with Victoria Avetisyan (mezzo-soprano), Deanna Johnson (flute), and Nune Hakobyan (piano and organ). Concert is free and open to the public. For information, call the church office at (617) 354-0632, or e-mail office@htaac.org.