Brecht and Weill are so well-known for Threepenny Opera that their other masterpieces are often ignored. Sarah Caldwell is presenting The Rise and Fall of the City of Mahagonny. The libretto, as bitter as any Brecht ever did, concerns a city whose only crime is if you cannot pay. Too bad most of us cannot pay for the tickets: the ones left are from $10 to $18. The sensible way to see Boston Opera Company productions is to enroll in their open-rehearsal subscription series.

Mark Silk returns to his old haunt, Adams House, for a flute and lieder program. Mark, one of the best flutists around Harvard for some time, is often remembered for his funny and incredibly diffident speeches requesting spare change to keep the Adams House Music Society running. K.T.H.

SYMPHONY HALL. Bernard Haitink conducting the BSO and Chorus Pro Musica. Mozart: Piano Concerto in B-flat (Nerine Barrett, soloist); Beethoven: Symphony No. 9. Tickets: 266-1492. April 13, 2:00 p.m.; 14, 8:30 p.m.; 17, 7:30 p.m.

ORPHEUM THEATER (413 Washington St.). Boston Opera Company. Weill-Brecht: The Rise and Fall of the City of Mahagonny. Tickets: 267-8050. April 13 and 15, 8:00 p.m.

ADAMS HOUSE JCR. Flute and lieder recital. Works of Mozart, Bach, Messiaen, Schubert, and Schumann. April 14, 8:30 p.m.

PAINE HALL. Robin Yuan, violin, and Myron Press, piano. Sonatas by Mozart, Brahms, and Franck. Tickets: $2.50 (students: $1.00). April 15, 3:00 p.m.

ADAMS HOUSE JCR. Pamela Gore, alto, singing Bach cantatas. Cantatas Nos. 169 and 170 at 3:00 p.m.; Cantatas Nos. 35 and 54 at 8:30 p.m. April 15.

PAINE HALL. Mile. Solange Corbin lecturing on trouvere chant. (Music Department) April 18, 4:15 p.m.