Pretty sure I put in a request back in 2016 for a dj subwoofer, needs to be a 12" cube capable of producing 128 db 15hz-120hz
6x 12" drivers would each require a one-way linear excursion of 143mm to produce 128dB@15Hz.
If we relax that to 35Hz, the one-way excursion needs to be 26mm, which feels possible.
This driver would probably get close:
https://stereointegrity.com/product/sql-series-12/Because there would be so many cones crammed into a tiny space, efficiency would be staggeringly low - around 80dB@1w, so the required power inputs would be phenomenal.
With six of those drivers crammed into a very very small box, you'd need around 100KW input to get the cones moving to their limits. That's a factor of 18x what they're rated for, well in excess of what's typically recommended.
So, with current technology it's not happening.
Bigger boxes help, but where's the fun in that?
Chris