Renée Fleming is Countess Madeleine, the beautiful, enigmatic woman at the center of Strauss’s sophisticated “Conversation Piece for Music.” She is being courted by two men: Joseph Kaiser sings the composer, Flamand, and Russell Braun is Olivier, the poet. The stellar cast also includes Peter Rose as the theater director La Roche, Sarah Connolly as the actress Clairon, and Morten Frank Larsen as the Countess’s brother. John Cox’s elegant production places the action in the 1920s. Andrew Davis conducts.