subwoofer problem

I have a shivasX2 driver that has suddenly stop working . i have tried 2 different plate amps on it . they both are starting on auto setting . i have checked all the connection & leads .

all that is happening is the driver is vibrating but you can only feel with your hand it is a constant hum it is the same using both plate amps i have checked the driver i cant see any damage.

does anyone have ideas on what the problem is thanks