Barbershop harmony is a style of a cappella music characterized by four-part chords for every melodic note sang by the lead. This style of a cappella is predominantly in homophonic texture.
Frequently sung in quartets, these quartets are mostly of one sex, being all-male or all-female. There are cases where the quartets are mixed. An all-male quartet is known as a barbershop quartet while on the other hand, all-female quartets are known as beautyshop quartets. In the quartet, the sound produced by the members should be very uniform, in terms of pitch, vowel pronunciation and tone. This ensures a well-balanced and well-blended singing.
In a quartet, there are four main parts: the lead, the tenor, the baritone and the bass. These four parts have the same name for both the all-male and all-female groups and do not have to correspond exactly to the parts of classical music with the same name. Each of the four parts has its own role.
The lead sings the melody line, which are familiar easily singable lines with understandable lyrics. The melody line is not usually sung by the tenor or the bass, but can sometimes be sung by the baritone part.
Harmonizing above the lead is the tenor. He sings the note that is the highest note in the four-part chord, most of the time harmonizing and not singing the melody. His part also can be a counter-melody to the melody that the lead sings. A counter melody is a sequence of notes that can be perceived as a melody when sung. However, it is almost always written to be sung together with a more prominent melody line.
Between the lead and the bass is the baritone, who sings the harmony line there which most of the time decides the tonality of the chord at that point. A baritone is a type of male voice that lies between a bass and a tenor. Finally, the bass sings the lowest notes in the four-part chord.
For a piece to be considered barbershop singing, some technicalities and criteria must be achieved or fulfilled.
The song in question must fulfill certain criteria as well. It must have easily understandable lyrics, sung to easily singable melodies. It must imply certain major and minor chords through the use of a tonal centre, and can also imply Barbershop seventh chords (the dominant seventh and the secondary dominant seventh).
The circle of fifths is also an important criterion that must be met. It is an imaginary geometrical space that depicts relationships between 12 pitches including chromatics. In barbershop music or harmony, the chords should resolve into each other using the circle of fifths, namely resolving from the dominant chord (V) to the tonic (I). Other resolutions of chords is also allowed, but not encouraged. The song should also be balanced and symmetrical. It is symmetrical in the sense that it starts and ends in the same way, in terms of lyrics and melody. The time signature must be standard, and slower songs should have a continuous beat.
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