Listen to Concerto 02 for piano and orchestra B flat major: Allegretto grazioso online. Concerto 02 for piano and orchestra B flat major: Allegretto grazioso is an English language song and is sung by Wilhelm Backhaus. Concerto 02 for piano and orchestra B flat major: Allegretto grazioso, from the album Instant Classical Culture, was released in the year 2010. The duration of the song is 2:57. Download English songs online from JioSaavn.