Cooper operated all five dummies and the projection of six voices. The extra voice was his, as he also had a role in the performance. In this scene, he multitasked by one of the dummies "cut the customer's hair" with his hands while using his feet to operate the other dummies.
Cooper oversaw all five dummies and the projection of six voices. He also had a part in the show, which is why there was an extra voice. In this scene, he juggled multiple tasks by having one dummy perform a haircut with his hands while using his feet to operate the other dummies.