When you walk into a U-M a cappella event, the audience’s deafening cheers and raucous cries of adoration might lead you to expect a rock god on stage. But the performers are all U-M students, and the performances are characterized more by a sense of wild, unpredictable fun than by strutting egos.

The singers, typically wearing color-coordinated outfits, grin widely as they harmonize their way through a wide variety of material. At last fall’s MACFest, fifteen groups offered unaccompanied renditions of folk tunes (the Civil Wars’ “Barton Hollow”), pop hits (Lorde’s “Royals”), a traditional Hebrew song (“Erev Shel Shoshanim”), and the jazzy classic “Feeling Good” with interludes in Mandarin Chinese. Beyond the elaborate multi-part vocals a cappella music is known for, most arrangements also rely on at least one performer for propulsive vocal percussion sounds, known as “beat-boxing.” There’s a giddy sense of enthusiasm, and a fierce sense of mutual support. Vocalists rush around nervously before performances and cheer their fellow groups afterwards. “We become each other’s audience and root each other on,” says Sarah Ikenberry, member of a group called the Harmonettes. “I was backstage [at MACFest] before every group went on, giving them cues, and everybody was just so complimentary and so excited. Groups that were passing would high-five each other and wish them to ‘break a leg.'”

Thing get a little more competitive this time of year, when the annual International Championship of Collegiate A Cappella (ICCA) comes around. U-M hosted a round of this year’s ICCA Great Lakes quarterfinals on February 15, and the regional semifinal will be held at Rackham Auditorium on March 15. Ikenberry says most of U-M’s groups aspire to a big win at the ICCA, and “everyone wants a Michigan group to make it to the final.”

Michigan’s a cappella community is one of the largest in the country–with sixteen groups, it tops even legendary a cappella schools like Yale (fifteen) and Cornell (twelve). The Michigan A Cappella Council (MACC) includes all-male, all-female, coed, Jewish, Christian, and South Asian ensembles. “It’s not the same as your typical New England a cappella group,” says Nina Peluso, a member and the business manager of a group called Amazin’ Blue. “A lot of people love to sing, but this gives people an opportunity to sing and do something that reflects their interests.”

Ikenberry, who is also MACC’s vice president, attributes a cappella’s surge in popularity over the last decade to its visibilty in entertainment like TV’s Glee or the 2012 film Pitch Perfect. “I think for a long time choir and singing were considered dorky things for people to do, so only the people that were serious about it were the ones that wanted to try out,” Ikenberry says. “But I think it’s becoming more of a cool thing. Now it’s considered OK to audition for these groups.”

In fact, Michigan’s a cappella groups can be even more selective than the university itself. Most groups interviewed for this story report significant year-to-year increases recently in the number of people auditioning during MACC’s fall AcaRush. Peluso says 100 tried out for Amazin’ Blue in 2012 and 140 last fall, while Ikenberry says the Harmonettes jumped from about eighty hopefuls to 100. Yet groups usually have fewer than five openings per year.

Hannah Nathans found herself a victim of that harsh reality when she arrived at U-M in 2010. Fresh off the Pioneer High School Bel Canto and A Cappella choirs, she auditioned for a few a cappella groups at U-M but didn’t get in. So she and some friends decided to do the next best thing: start their own group. The Sirens were accepted into MACC last winter and held their first official auditions last fall–at which point Nathans found herself in the difficult position of having to choose just three new members from a pool of eighty hopefuls.

“We really weren’t prepared for the amount of auditions,” she says. “It’s kind of sad in a way, because I didn’t want it to feel like this exclusive thing that I felt when I was auditioning.”

A cappella has come a long way since 1955, when Michigan’s first group, the Friars, spun out from the larger U-M Men’s Glee Club. Their early repertoire was more nostalgic than today’s pop re-creations, including twenties jazz standards like “Flamin’ Mamie” and “Toot Toot Tootsie.” But even then, the Friars and their audience had a sense of humor: in the group’s recording of the 1927 jazz tune “Take Your Finger Out of Your Mouth,” the audience can be heard howling with laughter at the song’s cheeky lyrics.

It took until 1979 for the Harmonettes to spin out of the Women’s Glee Club as the university’s first all-female a cappella group. These days, the options for an a cappella hopeful cater to more than just gender difference–although the “special interest” groups can be rather loosely defined. Kellie Rong is director of the �xADKopitonez, an “Asian interest” group. Rong says that although the Kopitonez are primarily Asian American, the group is open to anyone enthusiastic about Asian culture. “We’re definitely not exclusive,” Rong says. “We also have two Caucasian girls and a couple of Hispanic guys, so we’re decently diverse. Being ‘Asian interest’ is just to promote our culture as a whole.”

Although six U-M groups, including Amazin’ Blue and the Harmonettes, vied for a finalist spot in this year’s ICCA, the competition is marked by good sportsmanship. The G-Men have placed first in the regional quarterfinals two years running, but at U-M events, the group’s howls of support for fellow groups are louder than anyone’s. G-Men president Apoorv Dhir says the “intense, hostile rivalry” between groups in Pitch Perfect couldn’t be further from the truth. “It made me really uncomfortable, because at least at Michigan there’s nothing like that,” Dhir says. “We’re all really supportive of each other.

“We all compete at ICCAs and regardless of the outcome, nothing changes. We’re all still friends, and we’re all really happy for each other.”