like this or... bigger!

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https://www.soundandvision.com/content/ascendo-s-seismic-subwoofer-modern-marvel
"We wanted to know what it takes to design and build a subwoofer of this caliber — one capable of producing peak levels up to 140 dB and deliver 105 dB of sound pressure at 5 Hz. Is a subwoofer that weighs 441 pounds and uses a single 50-inch (!) driver"

. . .

"We designed a woofer with a huge voice coil almost 14 inches in diameter"

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Apparently they've also got an 80" model, personally I think the cone on the 50" looks better engineered though.

And not going to lie, I could use one of those 50" models myself, or a couple...

How would one get a powerful enough magnet to maintain over one Tesla in the gap at that physical size? Rob one from an NMR machine? And cyro-cool it?
Actually there are 90 MHz NMR bench tops nowadays, also using neodymium magnets.