(Credit: Jiyang Chen/Rabovsky) The Pierre Boulez Saal has announced its 2020-21 Season. The German hall will present some of the greatest soloists in the world, including numerous great vocalists. For the purposes of this article, vocal performances will be highlighted. Olga Peretyatko and pianist Elena Bashkirova perform a recital of Russian music by Shostakovich, Prokofiev, and Rachmaninoff. Performance Date: Sept. {…}