Listen to Violin Concerto in B-Flat Major, D. 121: I. Allegro non presto online. Violin Concerto in B-Flat Major, D. 121: I. Allegro non presto is an English language song and is sung by Federico Guglielmo. Violin Concerto in B-Flat Major, D. 121: I. Allegro non presto, from the album Tartini: Violin Concertos Box Set, was released in the year 2015. The duration of the song is 4:17. Download English songs online from JioSaavn.