Pentatonix

Pentatonix is an acappella group of five vocalists, Scott Hoying, Kirstie Maldonado, Mitch Grassi, Avi Kaplan and Kevin Olusola, originating from Arlington, Texas. The group won the third season of The Sing-Off on November 28, 2011 broadcast on NBC, singing an a cappella arrangement of "Eye of the Tiger" originally performed by the band Survivor as their victory song. Pentatonix won $200,000 and a recording contract with Sony - Wikipedia