Chris Willman Senior Music Writer and Chief Music Critic“Back to the Drive-In” is filmmaker April Wright’s second documentary about drive-ins, following 2013’s “Going Attractions: The Definitive Story of the American Drive-In Movie,” but she’s not milking a good thing with a rehash of the definitive first film. Rather than again explore the overall rise and fall and semi-rise of the phenomenon, in this terrific sequel, she’s looking at the big picture (drive-in screens are huge, in case you haven’t been) but also the smaller one, painting a series of portraits of 11 different ozoners across the U.S.