didnt know Barbershop music was a category of music.
Oh yes, it's a vocal harmony codified during the barbershop revival era. It's mostly a cappella
oh ok, seems kind of a dead art tho.
Oh, yes, it is a dying breed. But when it was in full swing it was mostly played by a barbershop quartet, a group of four singers.
Oh so barbershop quartets that makes sense, thought it was more inline of something like elevator music but it means quartets
Oh, yes the quartets usually have a lead, a bass, a tenor, and a baritone. They all harmonize together to entertain barber patrons. 
Oh yea thats really cool.
Isn't it though? Too bad most of them have died out, you might be lucky to find a female barbershop quartet somewhere, usually referred to as Sweet Adelines quartets.
what a weird name that is haha.
Sweet Adelines International
Sweet Adelines International is a worldwide organization of women singers, established in 1945, committed to advancing the musical art form of barbershop harmony through education and performances. This independent, nonprofit music education association is one of the world's largest singing organizations for women. "Harmonize the World" is the organization's motto. It has a current membership of 21,000 and holds an annual international singing competition.
History.
Sweet Adelines International was established in 1945 by Edna Mae Anderson of Tulsa, Oklahoma. The
Barbershop music
Barbershop vocal harmony, as codified during the barbershop revival era (1930s–present), is a style of a cappella close harmony, or unaccompanied vocal music, characterized by consonant four-part chords for every melody note in a predominantly homophonic 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. The melody is not