"From the wikipedia"
The Sing-Off is an American television singing competition featuring a cappela groups. It premiered on NBC on December 14, 2009, and is produced by Sony Pictures Television.
It is hosted by Nick Lachey, with judges Ben Folds, Shawn Stockman (of the R&B vocal group Boyz II Men), and originally Nicole Scherzinger, later replaced by Sara Bareilles. The show's music staff all come from the A cappella community: Deke Sharon, Bill Hare, Ed Boyer and Ben Bram.
A capella groups from the United States, including Puerto Rico, are chosen by audition and advanced in the competition based on judges' eliminations until the finale, with the winners being determined by viewer votes.
On February 22, 2011, The Sing-Off was renewed for a third season and is slated to air on September 19, 2011. Unlike previous seasons, this will start in September and will have more episodes produced.
|Season||Ep #||First Airdate||Last Airdate|
|Season 1||4||December 14, 2009||December 21, 2009|
|Season 2||5||December 6, 2010||December 20, 2010|
|Season 3||11||September 19, 2011||November 28, 2011|