Listen to Four Moravian Male Choruses: I. If You Only Knew online. Four Moravian Male Choruses: I. If You Only Knew is an English language song and is sung by Prague Philharmonic Choir. Four Moravian Male Choruses: I. If You Only Knew, from the album Janacek: Male Choruses, was released in the year 1995. The duration of the song is 2:18. Download English songs online from JioSaavn.