I have been attending annual Harmony Brigade rallys since 2006 and am a member of two brigades, the Atlantic Harmony Brigade (AHB) and the North Carolina Brigade (NCHB). I am one of the founding members of the AHB but I can not claim perfect attendance since I had to miss the 2010 brigade while I was working on my Bachelor's Degree.
Why do we call it eXtreme Quartetting? About 4 months before a rally weekend the guys who will be attending receive a music packet with sheet music and learning tracks for twelve high quality arrangements that have been made famous by international medalist-level quartets of the Barbershop Harmony Society. We are expected to have the music memorized by the rally and "coming unprepared is NOT an option." Friday afternoon of the rally the roughly 128 guys are formed into randomly selected quartets and are assigned one of the twelve songs we have all learned. We have one hour to rehearse and then gather for a quartet contest, singing with guys we may have just met! There are two rounds of contest adjudicated by a panel of 4 judges and the top 10 quartets advance to the second round which is held on Saturday. The judging panel usually consists of a well known District or International-level quartet.
Saturday afternoon the group assembles for a rehearsal as a large chorus. That evening the brigade puts on a show that is open to the public, featuring the judging panel as the headliners, the brigade chorus, and a parade of quartets who audition for the music team to be on the show. The rest of the weekend is spent in non-stop quartet singing and mixing it up trying to sing with as many of the participants as you can.
As of 2019 there are 12 annual brigades and each brigade agrees to include a core group of songs that make up part of the twelve song selection each year. This ensures that any brigader can hook up with guys from a different brigade and still have at least 8 songs in common for any given year. When the brigades moved across the pond to Europe the concept of mixed brigades was introduced. The Mixed Brigade of New England was created as a mixed brigade and the Atlantic Harmony Brigade voted in 2019 to become a mixed brigade!
While you are here check out my eXtreme Quartetting song history database project: http://gud2brabah.com/xq/database/.
See the links below to find out more information about each brigade.
AXQHB - Association of eXtreme Quartetting Harmony Brigades (https://home.harmonybrigade.org/)