Believe it or not, that thing inspired me to completely rethink how I reproduce sound in my house!
I now have hacked four holes into an otherwise serviceable door, added plywood to reinforce, (hollow core construction
and four subwoofers I rebuilt by hand which anyone else would have pitched into the bin!
Its a good thing the power amplifier that runs all that has overcurrent protection as it shuts down before the speakers bottom out if I run the gains up. Likely this has saved the speakers from certain destruction. Moreover this functions as a hearing protection device as the one-meter SPL approaches the limits of my metering equipment