Yea, how much weight can the floor hold per sq area? If someone slams on a record and the entire support falls through and kills someone, it's your ass that goes to jail.
What is bouncy, exactly? Being on the second floor, I'd think you would have much fewer problems with the subs or dancers. If the area around the booth is the problem, see if the floor joists can be decoupled, but also check about the integrity of the floor in general! Some rubber bands or squash balls might be all you need, but maybe you need a structural engineer to o.k. the entire thing!