How about that Barbershop music?  It's an interesting sound.
I agree, the harmonization is so nice to hear, don't you think? 
Indeed.  I wonder what the largest Barbershop music group is.
I'm not sure, but there is a Barbershop Harmony Society that promotes the art.
Oh cool.  Do you know when the Barbershop Harmony Society started?
It was founded in 1938 in Tulsa Oklahoma. 
Do you know how many members the Barbershop Harmony Society currently has?
focus is on "a cappella" music. The international headquarters was in Kenosha, Wisconsin for fifty years before moving to Nashville, Tennessee in 2007. In June 2018, the society announced it would allow women to join as full members.
A parallel women's singing organization, Sweet Adelines International (SAI) was founded in 1945. A second women's barbershop harmony organization, Harmony, Incorporated, broke from SAI in 1959 over an issue of racial exclusion, with SAI (like SPEBSQSA and many other organizations) being
of one or two barbershop songs with a personalized card and either roses or chocolates.
Song selection.
Each chapter is free to choose their own music. For male barbershop chapters, the typical two song selection is:
- "Heart of My Heart, I Love You" (the chorus from "the Story of the Rose"), and
- "Let Me Call You Sweetheart"
There are standard barbershop arrangements for these two songs from the Barbershop Harmony Society collection of twelve "polecat songs"