Listen to Brandenburg Concerto No. 6 in B-Flat Major, BWV 1051: I. Allegro online. Brandenburg Concerto No. 6 in B-Flat Major, BWV 1051: I. Allegro is an Instrumental language song and is sung by Leningrad Chamber Orchestra. Brandenburg Concerto No. 6 in B-Flat Major, BWV 1051: I. Allegro, from the album Bach: Brandenburg Concertos, was released in the year 1971. The duration of the song is 6:37. Download Instrumental songs online from JioSaavn.