(Credits: Håkan Flank / Theodora Richter / Harald Hoffmann) The Duisburger Philharmoniker has announced its 2021-22 season. For the purposes of this article, we will focus on vocal works only. A performance of Beethoven‘s “Missa Solemnis” stars soprano Julia Kleiter, tenor Christoph Prégardien, alto Ingeborg Danz, and bass Tareq Nazmi. Christoph Spering conducts the Chorus Musicus Köln. Performance dates: Sep. {…}