On another related note, drivers do also have an excursion limit. With enough power the driver cannot push any further outward physically and you will hear something like a banging noise.

If you want stupid volume sound, get the biggest speakers and driver sizes you can (e.g. the 'concert' size speakers), however i've had my M60s hit 106 dB before (around 12' distance) and that is 'stupid' loud.

"Those who preach the myths of audio are ignorant of truth."