Pentatonix

Pentatonix  (abbreviated PTX) is an American a cappella group from Arlington, Texas.  Characterized by their pop-style arrangements with vocal harmonies, basslines, riffing, percussion, and beatboxing, they are widely known for their covers, mostly of modern pop works or Christmas songs, sometimes in the form of medleys, along with original material.  Pentatonix formed in 2011 and subsequently won the third season of NBC’s The Sing-Off.  When Sony’s Epic Records dropped the group after The Sing-Off, the group formed its YouTube channel.  With over 13 million subscribers and 2.7 billion views, Pentatonix’s YouTube channel is currently the 50th most-subscribed-to YouTube channel.  Pentatonix have won three Grammy Awards:  They were the first a cappella act to win Best Arrangement, Instrumental or A Cappella.  (More from Wikipedia)