Barbershop music

Barbershop music is a style of a cappella close harmony and vocal harmony, or unaccompanied vocal music, characterized by consonant four-part chords for every melody note in a primarily homorhythmic 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. Short segments of bass or tenor melody, for variety or to feature particular singers, are not uncommon, but the bulk of the melody must be in an "inner voice" (lead or baritone; in practice almost always lead). In addition, parts other than lead may take the melody in passing tones to avoid awkward voice leading, in tags or codas, or when some appropriate embellishment can be created. One characteristic feature of barbershop harmony is the use of what is known as "snakes" and "swipes". This is when a chord is altered by a change in one or more non-melodic voices. Occasional passages may be sung by fewer than four voice parts.