Pitch Slapped

A cappella competitions are in vogue thanks to the recent popularity of "Pitch Perfect'' and its sequel, so it was only a matter of time before the activity got its own docuseries. "Pitch Slapped'' follows a cappella teams from two New Jersey high schools that are mentored by some of the best coaches in the industry as they face off in weekly competitions, leading up to a championship sing-off. Cherry Hill's Stay Tuned learns under the tutelage of Deke Sharon -- who was the on-site music direct…