LOS ANGELES, CA - NOVEMBER 22: (L-R) Singers Avi Kaplan, Mitch Grassi, Scott Hoying, Kirstie Maldonado and Kevin Olusola of m
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Pentatonix was not the first group to win The Sing-Off, nor the first a cappella group to land a major record deal, but the quintet are, by far, the genre's most successful act today. This year was a massive one for Scott Hoying, Mitch Grassi, Kirstin Maldonado, Avi Kaplan and Kevin Olusola, and it's because they're a lot savvier than people give them credit for. There's a reason why no other a cappella group is making the moves that PTX is making right now.

After winning Season 3 of The Sing-Off in 2011, the group was signed and later dropped from Epic Records. Beatboxer Kevin said in an interview earlier this year that the label "didn't believe that a cappella music could have a significant place in the industry." In hindsight, that setback may have been a blessing in disguise for an act trying to break a music industry that hadn't proven they were at all into a cappella yet.

Instead, the group focused on bringing whatever audience they had cultivated on the reality show and patiently growing it on YouTube, uploading their first video to the channel in 2012. That year is important in their trajectory, for reasons that have nothing to do with Pentatonix: That was the same year Pitch Perfect was released, became a sleeper hit at the box office and Anna Kendrick's a cappella-leaning "Cups" became a Top 10 radio hit. The film helped get a cappella on the mainstream's collective brain, but where Pentatonix varied from their contemporaries like Straight No Chaser (the Indiana University male group who signed an album deal with Atlantic Records in 2008) was in their individual personalities. Pitch Perfect was a hit because it paired a cappella music with charismatic personas (who didn't love Rebel Wilson as Fat Amy?); in their own way, Pentatonix followed the same formula.

Fans quickly learned to identify Avi's stoic-but-warm demeanor, Mitch's sass, and all the other PTX members' different personalities on social media and through their videos; the group almost always left a cute message to fans at the end of their covers. Most notably, Scott and Mitch have a splinter channel, Superfruit, with nearly two million subscribers, and includes everything from covers to interviewing fellow YouTube celebs to the guys getting drag makeup done. Comparatively, Straight No Chaser was a university group that didn't have a fixed lineup, making it tough for fans to really latch onto the group itself.

Pentatonix cultivated that strong and dedicated fanbase, but there was still the looming question of how they would be able to translate the palpable excitement their fans had for them (they boast millions of YouTube, Twitter and Facebook followers between their group and personal accouts) to any type of mainstream reaction. This was another key part of PTX's road to success: they put out a full-length holiday album prior to an original full-length.

By its nature, a cappella can't really sound trendy, since it's composed solely of voices. The style has a traditional element that lends itself perfectly to Christmas staples. Pentatonix found a sweet spot with their holiday tunes that were much more accessible for a wider audience to digest—especially the younger audience that was sick of having the classics shoved down their throats since Halloween ended. Their refreshing rendition of "Little Drummer Boy" in 2013 hit No. 13 on the Billboard Hot 100, followed by a cover of "Mary, Did You Know?" hitting the Top 30 a year later. The latter track was lifted from their first full-length album, That's Christmas to Me, which went on to sell more than a million copies and being a best-seller.

At that point, the group started to snag big promotional opportunities traditionally given to pop superstars, including the Macy's Thanksgiving Day Parade, Dick Clark's New Year's Rockin' Eve, a cameo on Disney Channel's K.C. Undercover, and even an opening slot on Kelly Clarkson's 2015 U.S. tour. It was from here that the group was finally able to make an honest attempt at transitioning into their own original music. This came in the form of their Pentatonix album—their first release that wasn't a majority of covers, issued in October, one year after their holiday release. The result? The No. 1 album in the country that week, even reigning over pop force Demi Lovato's new Confidence LP on the Billboard 200. A major win for Pentatonix and, undoubtedly, a major win for choir nerds everywhere.

Pentatonix has established themselves in the mainstream world, and did so by making business moves and personal touches that allowed the once-tepid mainstream to warm up to their unconventional brand. Once disregarded, the self-described a cappella "underdogs" are now roundly, deservingly embraced.