A program titled “Voices of Vienna” might conjure expectations of either Joseph Haydn’s light classicism or Alban Berg’s expressionist atonality. However, the Colburn School’s concert featured works by Hugo Kauder, Eric Zeisl, Ernst Toch, and Ernst Krenek—four lesser-known composers thrust into relative obscurity by Nazi oppression and overshadowed by prominent names of the Second Viennese School and the Golden Age of Hollywood….