Pentatonix, aka PTX, gained fame when they won the thrid season of NBC's The Sing-Off. This American a cappella group covers old and new songs by creating their own arrangements and vocal harmonies along with beat boxing. Sharing these projects on YouTube has garnered them 10.8 million subscribers. Recently, they collaborated with Jason Derulo. They're coming to Seoul for they World Tour 2016. Don't miss they amazing performance.