while we are all thinking about voltage drop on the neutral, vs the ground think about what happens when a surge protector does its thing. A giant surge hits the AC feed to the booth. The surge protector connects that crazy high voltage on both hot and neutral to ground. Current flows through the ground developing a voltage. Let's say 100 volts for just an instant. No problem. The equipment has been saved.
But. There is a audio cable from the mixer in the booth to the amp on the platform. Now the amp that didn't get a surge sees 100 volts coming down pin one. It's own ground is (or was) at zero. At this point bad stuff happens
Answer, a surge protector like Surge-X that clamps the hot and neutral together.