Like many 14-year-old boys, Sam Koltun is soft-spoken, with braces, eyeglasses and a face partially hidden behind locks of hair.

So it comes as a bit of a surprise to see him on stage with his rock band, the Switchfits, wearing a black bandanna and wrist cuffs with skulls. When he leads the band into the punk-inspired original tune "Hey Hey," it's like a beast overtakes his vocal cords to roar, "One, two, three!"

Sam and his bandmates — Harry Russell, 14, and Tony Pepper, 17 — are the only St. Louis-area semifinalists in a national battle-of-the-bands competition worth thousands of dollars in prize money for the young musicians and their schools.

Teens in more than 200 bands across the country each submitted three songs they wrote and performed, and SchoolJam USA's organizers narrowed down the field to 10 semifinalists in each of five geographic regions. The final 10 will be decided by an online voting period that ends Dec. 5.

The Switchfits — Sam's a freshman at John F. Kennedy Catholic, Harry's a freshman at Kirkwood High, and Tony is home-schooled — have taken to school hallways and to Facebook, MySpace and Twitter to get the word out about voting.

"It's frustrating because this part is really more about a popularity contest, not our music," said Tony, the Switchfits' drummer. "So we're just begging everyone we know, 'Please, vote for us.'"

Teaching the high school musicians how to market themselves was part of the idea behind SchoolJam USA, said Morgan Ringwald, director of market development for NAMM, a trade group that runs the competition and represents the international music-products industry.

"Part of being a band is not just making music, it's marketing," Ringwald said. "They've got to know how to promote their talents."

Of course, that's easier to do on a major-label budget than on a teenage allowance. The Switchfits' equipment includes a guitar Sam bought for a penny on eBay, and the teens rely on their parents to drive them to gigs, such as a recent one in Hot Topic at the Chesterfield Mall.

"We want to help them in any way we can, because we know how talented they are and how much they love playing," said Ben Koltun, Sam's dad. "But we only let them do their thing if their grades are up and their homework is finished."

The band practices in the Koltuns' basement in Chesterfield on Fridays and plays in an open-mike event most Monday nights at House of Rock; but other venues, with an over-18 policy, such as Blueberry Hill, have turned away the Switchfits.

For a moment, the band called itself the Switch — fitting because the three often switch instruments, with Harry on drums and Tony on bass or guitar, and because it's the name of an organic juice Harry's mom likes him to drink instead of soda. Turns out, the Switch was also the name of an R&B band from the '70s and '80s. So, after a long brainstorming session, the Switchfits were born.

"It's sort of like the Misfits, plus it just sounds cool," Sam said.

Sam, Harry and Tony met about two years ago at a summer band camp. All three have been playing for several years — Harry picked up classical violin at age 5, and Tony began beating on couches with drumsticks at the same age.

Their practice space has posters of Guns N' Roses, Green Day and Kurt Cobain, and they cite musical influences from Slash and the Who drummer Keith Moon, to Jesse McCartney and the All-American Rejects.

Their musical repertoire is just as diverse, with original songs firmly rooted in pop-punk and alternative rock that showcase Harry's vocals, Sam's guitar work and Tony's drumming. They've also played rock covers of "Jingle Bells" and Soulja Boy's "Kiss Me Through the Phone." During the Cardinals' early playoff hopes this year, the Switchfits rewrote the lyrics to "Hey Hey" into a team-spirit song, "On Our Way."

All three say they want to make careers out of music, with Harry conceding he'd also consider architecture or playing soccer. For now, they have their hopes set on making the SchoolJam finals and getting to play for a live audience.

"They have what it takes to win," said Ron Roskowske, Kennedy High's music director, who conducts Sam's school jazz ensemble. "They are a very tight band. They understand the importance of practice, and they all have a good grounding in musical education."

If the Switchfits get enough votes to advance to the finals, the teens will fly to California to compete for judges. The winning band members get $750 and a chance to play at an international SchoolJam performance in Germany, and their schools' music programs will share $5,000.

"I know Sam would like me to get a new guitar amplifier in here if they win," Roskowske said. "I've got some drums and things that are badly in need of repair. A new piano would be nice."