The Society for the Preservation and Encouragement of Barbershop Singing in America (SPEBSQSA) is devoted to promoting, preserving, and enjoying a special form of harmony known as "barbershop harmony" which is different from other forms of 4-part a cappella singing. Not all songs can be arranged as barbershop style music which brings up the question: "What makes a particular song or arrangement "barbershop-able"? What is the difference between barbershop and doo-wop, jazz, madrigal, and other a cappella music?
Technically speaking, barbershop harmony is a style of unaccompanied singing with three harmonizing voices plus the melody. The lead usually sings the melody, with the tenor harmonizing above the lead. The bass sings the lowest harmonizing notes and the baritone provides in-between notes, either above or below the lead to make completed chords (specifically, dominant-type or "barbershop" sevenths). This gives barbershop its distinctive, "full" sound.
Probably the most distinctive facet of barbershop harmony is the phenomenon known as "expanded sound" which is created when the harmonics in the tones reinforce each other to produce audible overtones or undertones. Barbershoppers call this "ringing a chord" Singing in a quartet or chorus and creating that "fifth voice" is one of the most thrilling musical sensations you'll ever experience, leading to goose bumps the size of golf balls.
Oh yes ! - and on street corners where it was sometimes called "curbstone" harmony, in parlors, at social functions and it was common on early radio broadcasts where four men could sing into a single microphone. Barbershop's roots are not just in the white, middle-America of Norman Rockwell's famous painting. Rather, barbershop is a "melting pot" product of African-American musical devices, European hymn-singing culture, and an American tradition of recreational music - a tradition the Society continues today.
Minstrel shows of the mid-1800s often consisted of white singers in blackface or black singers themselves performing songs and sketches based on a romanticized vision of plantation life. As the minstrel show was supplanted by the equally popular vaudeville, the tradition of close-harmony quartets remained, often as a "four act" combining music with ethnic comedy that would be scandalous by modern standards.
The "barbershop" style of music is first associated with black southern quartets of the 1870s, such as The American Four and The Hamtown Students. The African influence is particularly notable in the improvisational nature of the harmonization, and the flexing of melody to produce harmonies in "swipes" and "snakes." Black quartets "cracking a chord" were commonplace at places like Joe Sarpy's Cut Rate Shaving Parlor in St. Louis, or in Jacksonville, Florida, where, black historian James Weldon Johnson writes, "every barbershop seemed to have its own quartet."
The first written use of the word "barbershop" when referring to harmonizing came in 1910, with the publication of the song, "Play That Barbershop Chord" - evidence that the term was in common parlance by that time.
The songwriters of Tin Pan Alley made their living by appealing to the needs and tastes of the recreational musician. To become a sheet music hit songs had to be easily singable by average singers, with average vocal ranges and average vocal control. This called for songs with simple, straightforward melodies, with heartfelt, commonplace themes and images. Music published in that era often included an instrumental arrangement for piano or ukulele, and a vocal arrangement for male quartet.
The phonograph made it possible to actually hear the new songs coming from Tin Pan Alley. Professional quartets recorded hundreds of songs for the Victor, Edison, and Columbia labels, which spurred sheet music sales. For example, "You're The Flower Of My Heart, Sweet Adeline" captured the hearts of harmony lovers, not simply because it easily adapted to harmony, but also because it was heavily promoted by the popular Quaker City Four and other quartets.