Did anyone see that episode of mythbusters when they made the 51 inch woofer that was powered by the crankshaft of a diesel powered benz? It reached 161db @ 16Hz before blowing out the sun roof and letting the internal pressure out. When the pressure released it self destructed. An episode well worth seeing.
Just my opinion, but I thought it was crap....it didntlat very long, and I dont consider what they built to really be a subwoofer...like muddy said, they should redo that on with amps and subs.