Barbershop music, usually referred to simply as "barbershop", is a style of a capella music that uses four-part harmony. It is distinguished from other styles of four-part a cappella by several characteristics, namely:
- The melody is sung, with rare exceptions, by the second tenor, known as the "lead". The first tenor, known simply as the "tenor", harmonizes above the lead. The bass sings the bottom note, and the baritone sings whatever note of the chord is left over, usually between the lead and the bass but just as often between the lead and the tenor.note
- The four parts sing homophonically - that is, all four are singing the same lyrics at the same time.
- Melodies tend to adhere to chord progressions that resolve around the Circle of Fifths, with heavy use of a few other progressions.
- Chords utilize close voicings, and whenever possible, all four singers sing their own distinct note in the chord (octaves are discouraged except to begin or end a melody line).
- The lyrics are easily understandable.
Barbershop music first developed out of informal a cappella singing in the latter half of the 1800s. The style was likely invented by African-Americans who sang in the fields, on street corners, or in communal gathering spaces like barbershops. White men quickly adopted the hobby as well, but the term "barbershop" initially referred exclusively to black quartets; white groups were known simply as "male quartets". Barbershop became a popular fixture in vaudeville and in the fledgling recording industry, but the professional quartets were vastly outnumbered by amateur groups who sang on the street for the simple pleasure of ringing chords. Many of these young men would take what they learned singing barbershop and apply it to the newborn genre of jazz, including such greats as Louis Armstrong and Jelly Roll Morton.
Barbershop's popularity waned through the late 1920s. Eventually, in 1938, a group of former enthusiasts established the Society for the Preservation and Encouragement of Barber Shop Quartet Singing in America (SPEBSQSA), and held a quartet contest in New York City in the summer of 1939. The contest has been held every year since. SPEBSQSA, now known as the Barbershop Harmony Society (BHS),note remained an all-men's organization until 2018; women barbershoppers have societies of their own - Sweet Adelines International (SAI), established in 1945, and Harmony, Incorporated, which split off from SAI in 1959. These organizations together number around 50,000 members. There are affiliate barbershop organizations in Great Britain, Australia, New Zealand, Germany, the Netherlands, Finland, Ireland, Spain, Sweden, and South Africa.