It would not be World of Bluegrass without some truly impressive super-group star power, and there’s plenty of that in The Ringers. The group’s lineup includes Jerry Douglas, ringleader of three-time IBMA entertainers of the year Earls of Leicester; Dan Tyminski, of “Man of Constant Sorrow” fame; mandolin master Ronnie McCoury, son of Del and one of the great bluegrass scions; fiddle innovator Christian Sedelmyer; and, along with bassist Todd Phillips holding it down.