Listen to I. Allegro assai online. I. Allegro assai is an English language song and is sung by Bamberg Symphony Orchestra and Istvan Kertesz. I. Allegro assai, from the album 20 Basics: Haydn (20 Classical Masterpieces), was released in the year 2015. The duration of the song is 6:01. Download English songs online from JioSaavn.