Listen to Piano Concerto No. 4 in G Major, Op. 58: I. Allegro moderato online. Piano Concerto No. 4 in G Major, Op. 58: I. Allegro moderato is an English language song and is sung by Wilhelm Backhaus. Piano Concerto No. 4 in G Major, Op. 58: I. Allegro moderato, from the album 100 Mellow Classics for Relaxation, was released in the year 2014. The duration of the song is 17:29. Download English songs online from JioSaavn.