Listen to Bassoon Concerto in B-Flat Major, RV 501: IV. Allegro online. Bassoon Concerto in B-Flat Major, RV 501: IV. Allegro is an Instrumental language song and is sung by Leningrad Chamber Orchestra. Bassoon Concerto in B-Flat Major, RV 501: IV. Allegro, from the album Antonio Vivaldi: 7 Concertos for Wind Instruments, was released in the year 1971. The duration of the song is 3:12. Download Instrumental songs online from JioSaavn.