Pentatonix: ’Angels We Have Heard On High,’ Live On Soundcheck

Hear the entire interview and session: Reality singing competitions have created their share of pop stars over the years -- and one of the newest additions to the club is Pentatonix. The Texas-based a cappella group won NBC’s ’The Sing-Off’ back in 2011, earning $200,000 and scoring a recording contract with Sony. Since then, the group has put out two full length albums, a Christmas EP, and racked up hundreds of millions of YouTube views.