Barbershop singing is a truly American style of music. It is four-part harmony sung without instrumental accompaniment. In barbershop harmony, the melody is sung by the lead, while the tenor part is sung above the lead. The bass part sings lower than the lead and the baritone provides the in-between notes that complete the chords which give barbershop harmony its distinctive four-part sound. When sung with precision, barbershop harmony produces additional notes referred to as "overtones".