Watch Series: The Sing-Off Released in (2009) - Season 4 produced by CA, USA, The TV Series categorized in Reality-TV, Family, Game Show, Music, and content rating TV-G with duration 120 min broadcasted as these networks NBC, Streamed at Putlocker & directed by Michael Simon, Ivan Dudynsky, Joel Gallen. Featuring the country's best a cappella groups performing popular songs like you've never heard them before. There's no lip-synching, backup bands or safety net. They'll be singing for America's vote, with the winner walking away with the ultimate prize - a Sony Music recording contract and $100,000. - Season 4