Mann, who held professorships at Rutgers University and the Eastman School of Music in Rochester, was noted for his research on Austrian composer and musical theorist Johann Joseph Fux (1660-1741), whose writings illuminated 18th-century performance practice and influenced the current early music movement, according to the paper. Mann also championed Handel's lesser known music in the mid-20th century, helping to usher in the current Handel revival.
As a performer, Mann played the recorder and double bass professionally. His son, Adrian, is principal bassist and manager of the Fort Wayne Philharmonic.
Mann was also a choral conductor and led the Bach Choir of Bethlehem in Pennsylvania and the Cantata Singers in New York. He edited the American Choral Review and a number of papers for collected editions of Fux, Handel, Mozart and Schubert, according to the Times.
Mann was born in Hamburg, Germany, in 1917; his mother was the keyboardist and writer Edith Weiss-Mann. He studied at the Milan Conservatory in Italy and at the Berlin Hochschule f‹r Musik.
He emmigrated to the United States with his mother to escape the Nazis and continued his education at the Curtis Institute and Columbia University.