Actually, the story that was told to me by a senior design engineer from Alpine (car audio company)... was that in or around 1980, Cerwin-Vega took an 18" woofer, attached a fiberglass boat seat to the back of the magnet (so that you could sit on it, while the woofer was facing face-down on the floor), and wired an extension cord from the woofer input terminals to a variac. They then gave "rides" on the woofer... someone (usually a small child) would sit in the seat, and they'd ramp up the voltage until the 60Hz cone movement would produce enough sound pressure to "float" the speaker... not unlike an air-hockey table. Then, they'd push around the kid... the speaker/seat/rider would just "whoosh" across the concrete trade show floor...
Hey, it had all the elements for a gearhead good time... speed, noise AND power!
Regards,
Gordon.