Born in Sangerhausen, Braun studied musicology at the Martin Luther University of Halle-Wittenberg from 1946 to 1950 with Max Schneider and school music with main instrument piano and Germanistics.
At the end of 1961, Braun left the German Democratic Republic with his wife and children and became a Privatdozent at the Christian-Albrechts-Universität zu Kiel, combined with a research position.
After the formal abolition of the chairs by the Saarland University Act in the later 1970s, Braun was given the title of "Professor for life" (salary scale C).
Within the Neue Handbuch der Musikwissenschaft edited by Carl Dahlhaus and Hermann Danuser, Braun wrote the volume on 17th century music (1981), and in the edited collection Geschichte der Musiktheorie he is author of the volume on the historical development of German music theory from Sethus Calvisius to Johann Mattheson.
Braun wrote (until 2007) 15 monographs, about 140 scientific essays and 38 articles for the new edition of the encyclopedia Die Musik in Geschichte und Gegenwart (1994-2007).