Questions for you Revel owners

Anyone know if a working Revel subwoofer driver is more rigid than most. A buddy of mine recently moved out of state and is explaining to me that when he pushes lightly on the diaghram of the cone it doesn't move at all. This is the older non powered Ultima sub. A local shop has helped him diagnose it and they confirmed that his amp that was driving it is bad, but I have a sneaking suscpision that when he gets the amp repaired the driver will still be problematic.

Unless it uses a drone cone or passive radiator of some sort.

Does anyone have any insights?