For those of us who have had the pleasure of being in the audience at a Triple Trio performance, it’s always a highlight, eagerly anticipated in any program. While the other Spence choral groups perform beloved perennial favorites—what is the Winter Concert without “Jingle Bell Rock” or the Spring Concert without “Danny Boy”—the Triple Trio repertoire changes every year, giving an opportunity for the group to evolve, metamorphose and reinvent itself. In other words, the songs change as the group changes; Triple Trio, of all the vocal groups at Spence, is the only one run by students. Longtime music teacher Evan Wels serves as the advisor and says, “I give them space.”

Triple Trio has a certain mystique. To get that girl-group sound that reaches into the hearts of their parents, teachers and fellow students, members rehearse twice a week at Spence in the early morning, well before most teachers are ready to rock and roll. They also get together on Sunday evenings, with each taking a turn to play host. This responsibility includes supplying plenty of snacks and, once upon a time, a keyboard. Nowadays, a computer does the trick.

Triple Trio formed in 1964, when The Beatles also arrived on the scene. Created as an offshoot of Glee Club, the a cappella ensemble was the answer to a need for some group members to scratch an itch in the form of an independent streak. This was, after all, the mid-60s. As Triple Trio matured, the music has and continues to reflect the time.

The group’s structure: depending on the number of songs in a given year—usually 10 to 12—each Triple Trio member performs a solo, with priority going to more senior and experienced participants. Group songs are also performed, with several soloists contributing their talents, such as in the ensemble’s first song of 2013-2013, “Let it Be,” arranged by senior co-head Daisy Kramer. According to senior Kelly Brickell, “As senior co-heads, Daisy and I choose and arrange all of Triple Trio’s songs. Every girl auditions for every song and they we choose the soloist. We also choose and arrange our own solos.”

Leading the group requires well-honed musical competency and leadership skills. Preferred job qualifications in a Triple Trio club head are experience in choral music, and the ability to arrange music and play a musical instrument. At the end of the school year, Triple Trio members professionally record their songs in a music studio, leaving a lasting legacy of their unique sound.

The name Triple Trio: originally the group was only nine members and the plan was to have three groups of three girls. Now, the size fluctuates. This year there are 12. The makeup is a twist on the norm. Usually there are more older girls in Triple Trio than younger, but attrition from last year’s graduation allowed six new singers to join the group: the four freshmen, one sophomore and a junior.

At 7:15 a.m. on a frosty Thursday in February, the Triple Trio singers wandered quietly into the Donatelli Music Room on the second floor of the Townhouse. They assembled in a circle while Kelly looked intently at her laptop screen. The warm-up began and their voices grew stronger as they trilled up and down the scales. There was a bit of business to handle before getting down to rehearsing. Daisy went through a quick list, ending with a reminder about a performance at the Interschool Acappellooza in March. Then sheet music was handed around and musical notes emanated from the laptop. The girls singing soprano began, “All systems go…” from “Radioactive” by Imagine Dragons. All chimed in when signaled to do so, moving on to the lyrics “the apocalypse.” As the girls struggled with some of the higher notes, Kelly suggested with good humor, “Maybe not in the morning.” Sometimes individually, sometimes in groups of two or three, the vocalizations grew stronger. “One, two, three, four,” and the whole group began to sing—a big spine-tingling sound. Voices high, midrange and low joined together, some sang faster rhythms, some slower. Each part was arranged to work with the others, the melodies weaving together to take on a life as a full-bodied work. As members hit a more challenging section of the arrangement, Kelly said encouragingly, “I know it’s hard; let’s just try.” The voices came together again, the volume increasing. The group paused when they needed to untangle who would sing what and when. At the end of the 55-minute session, Kelly looked up from her computer, “That was actually good. We will continue on Sunday.”

Check out this video of Triple Trio performing a classic song by the Beatles.