The second season of last fall’s NBC-TV runaway hit The Sing-Off goes back into production with episodes slated to be recorded August 16 and 23 and September 2 and 8 at NBC’s Culver City, California studios. Last year’s host, Nick Lachey, and panel of judges, Ben Folds, Shawn Stockman and Nicole Scherzinger, are scheduled to return. Free audience tickets are available and being issued on line while they last.