Simply defined, barbershop harmony (sometimes referred to as 'four-part harmony') is vocal music consisting of four-part chords. It's always performed 'a cappella' (without accompaniment), though all 'a cappella' singing is not necessarily barbershop harmony.
The number of different singing parts, or voices, in barbershop harmony is always four, which are called lead, tenor, bass and baritone. This means a quartet consisting of one of each is the minimum number of singers required, with no limit to the maximum number of singers -- as in a chorus, as long as only the four parts are sung.
The melody is primarily sung by the lead, with the tenor singing harmony at a higher pitch. The bass sings the lowest notes, and the baritone completes the chord, sometimes above the lead's pitch but normally below.
To explain further, barbershop harmony consists of major and minor chords and barbershop (dominant and secondary dominant) seventh chords that resolve primarily around the circle of fifths, while making frequent use of other resolutions.
Fortunately, this simply boils down to each of the singers learning their respective parts using preprinted, prearranged music and words specially written and arranged for Barbershop Harmony, then rehearsing until words and music are memorized. This is done before performing to better allow each singer to focus on delivery.
If this sounds complicated, it really isn't. We welcome visitors at our High Country Harmonizers chorus rehearsals. Come see and hear for yourself how this information is put into practice. Our chorus invites men of all ages who love to sing and have fun to become a part of our chapter.
Always looking for good men to sing great music.