Barbershop vocal harmony, as codified during the barbershop revival era (1930s–present), is a style of
a cappella close harmony, or unaccompanied
vocal music, characterized by
consonant four-part
chords for every melody note in a predominantly
homophonic texture. Each of the four parts has its own role: generally, the
lead sings the melody, the
tenor harmonizes above the melody, the
bass sings the lowest harmonizing notes, and the
baritone completes the chord, usually below the lead. The melody is not usually sung by the tenor or baritone, except for an infrequent note or two to avoid awkward
voice leading, in
tags or
codas, or when some appropriate
embellishment can be created. Occasional passages may be sung by fewer than four voice parts.