Reality versus models: what we learned from acoustic control experiments

The development of active acoustic control experiments demonstrates the need to calibrate our view of the physical world with regular testing. We started with a desire to use feedback-based active control on acoustic systems with a system model based on the wave equation and the opinion that all work would flow smoothly from that model of physical reality. We have now realized that the hardest issues associated with active acoustic control are not well described by our simplistic initial model. Physical testing is the vehicle through which we tested our initial model. With physical testing and experimentation, we have focused on those elements of acoustics that are most important to the success of our acoustic control methods. The control experiment caused a change in research direction from control design to actuator design.