cantare la quinta parte

Instruction found in Frescobaldi's Capriccio obligo di cantare la quinta parte (Capricci, 1624, No. XII): the performer is required not only to play the four written voices but to sing a fifth, hidden voice aloud while playing. The fifth part (quinta parte) is not written out — the performer must discover it themselves. The challenge is both technical (singing and playing simultaneously in counterpoint) and interpretive (finding the voice that the composer has concealed within the harmonic structure). Frescobaldi remarks in his prefatory letter that he himself had \"a good tenor voice\" (buona voce di tenore), and the hidden voice is written for that tessitura.

Take \"cantare la quinta parte\" literally: Frescobaldi intends you to actually sing. The hidden voice can be identified by listening for lines that complete the harmonic logic at moments where the four written voices leave audible gaps. Approach the piece as an ensemble work in which you are simultaneously conductor, all four instrumentalists, and the singer. The added vocal line fundamentally changes the experience of the capriccio — it is no longer abstract counterpoint but a conversation between performer and score. Whether you choose to sing in performance or not, the process of finding the voice transforms your understanding of the piece.