MTV and Sean “P. Diddy” Combs on Thursday announced a second season of “Making the Band 3.” At the end of the first season, Mr. Combs decided he didn’t have enough talent to make a girl group, so he’s bringing back the three top finishers from the first season to compete against a new crop of aspiring singers. The new series is scheduled to premiere in the fourth quarter. Production will begin with an open call for auditions that will begin in New York on May 19. Other casting sessions will be held in Washington, Virginia Beach, Va., Orlando, Fla., Detroit, Minneapolis, Dallas and San Francisco.