A hundred screaming girls in a room too small for Cody Simpson. This about describes his stop at The Firebird in downtown St. Louis on Jan. 31.

“Wow, over a hundred” Justin Sinclair, tour manager/production guy/sound board operator, says as he leans over to The Firebird’s sound guy, “that’s a lot; but we got over 160 in Montreal.” He’s talking, of course, about the decibels of sound at which these teenage girls are screaming for 17-year-old Simpson.

Simpson was born and raised in Gold Coast, Australia. He was discovered in 2009 by a local radio company, and later began releasing singles, and, eventually, his first album, with Atlantic Records. His most recent release, “The Acoustic Sessions-EP,” showcases his subtle switch from pop music to more of a beachy, indie sound.

In several interviews, Simpson has discussed his love of music by Jack Johnson, John Mayer and Justin Timberlake. Until now, he hadn’t been able to express that kind of sound through his own music. Simpson was previously tied to artists like Justin Bieber, making it difficult for him to break out of the pop bubble. Now, with all the success he’s had creating a fanbase of devoted females, he’s allowing himself to add some more grown-up sound to his music.

This tour perfectly showcased his transition into softer, more grown-up sound. The setlist, though featuring almost all of Simpson’s hit songs (acoustically remastered, of course) included Avicci’s “Wake Me Up,” a mashup of JT’s “LoveStoned” and the ever-popular funk hit “Superstitious,” and “Stir It Up,” one of Simpson’s favorite Bob Marley songs.

Sinclair had a great time working on the project. He was the mastermind behind the whole tour, taking on production, management, soundboard and mentoring Simpson throughout the entire experience. When asked about being the only crew member, Sinclair said, “You gotta wear a lot of hats in this business. The more jobs you can do, the more valuable you are to somebody’s team. But still, it’s very, very hectic.”During the St. Louis show, several things went wrong with the soundboard despite several hours of soundcheck earlier that day. There was lots of running back and forth between the stage for both Sinclair and Simpson’s other manager, also that of Ariana Grande, The Wanted and Justin Bieber – Scooter Braun.

Despite the fact that nothing went as planned, Sinclair still commented that running the soundboard live is his favorite part about being on tour. “I love mixing the shows. I do a lot of other things, like production, but it all comes down to mixing the show. All the hard work, all the drama that happens during the day, this is the most fun part right here.”

Simpson has officially finished his “Acoustic Sessions” tour and is now back in the studio.