Aspiring musicians who saw the Academy Award-winning 2014 film “Whiplash” might have been frightened by conductor Terence Fletcher’s ruthless approach to drum instruction. Teaching at a fictional elite music school, Fletcher, portrayed by J.K. Simmons, is abusive in his tactics to get the best he can get out of his students. Jim Pitts, the real-life drum instructor at Opus School of Music, takes a different path to teach the 20 students who come to him for lessons. He’s kind, supportive, energetic and funny. “There’s our firecracker,” said Opus school owner Rob Melton, 48, when Pitts arrived on a recent Tuesday afternoon. Pitts, 67, sometimes does stand-up comedy.