The Philadelphia Singers, under the direction of David Hayes, close their season at 8 p.m. Saturday with Rachmaninoff's flowing Vespers (the All-Night Vigil, sung in Church Slavonic), Thomas Tallis' 40-voice "Spem in Alium" and John Tavener's 1995 "Syvati" for solo cello and chamber chorus. Hayes has chosen an unusual but ideal venue for this concert: Congregation Rodeph Shalom at Broad and Green streets. Tickets: $25-$32. Info: 215-893-1999.
Bach's monumental B Minor Mass, perhaps the summit of sacred music, has been chosen for Singing City's 54th anniversary concert. To be held at 7:30 p.m. Saturday at Bryn Mawr Presbyterian Church, 625 Montgomery Ave. Helmuth Rilling conducts the chorus and the Chamber Orchestra of Philadelphia. Tickets: $20-$30. Info: 215-569-9067.