https://www.aia-cinema.com/products/the64-sub-pro-passive-se...
https://www.aia-cinema.com/products/the100-sub-pro-passive-s...
Having to listen to others bad music, even if I don't want to?
> It captures both the weight of a collapsing mountain and the whisper of tectonic tension with equal ease.
> THE100 SUB PRO PASSIVE doesn’t just play low frequencies — it summons them from the earth itself.
Edit: apparently the site is translated from its original Japanese version, which explains these weird wordings.
The original article is here, which has more pictures too: https://audio-heritage.jp/DIATONE/diatonesp/d-160.html
Mounted to the front of a forklift I'd have to say that's a loud horn!
Direct-radiating bass reproduction is all about displacement, and the area of the piston (cone) is certainly a factor of that. More tends to be... well, more.
And this mysterious speaker (which there seems to be no color photos of, despite the 1981 date) has a radiating area of perhaps about 2 square meters.
That's around the same as qty. 18 of 18" woofers.
It's easy to find collections of way, way more than that. People even charge money to hear them; they're on the ground between the stage and the crowd barrier at any big rock show. :)
https://www.udco.com/products/electrodynamic-shaker-systems/...
(The Restaurant at the End of the Universe, Douglas Adams)
> The outdoor test seemed to have a negative impact on the neighborhood. At a distance of about 100m from the speaker, it was felt as sound, but at a distance of more than that, it was transmitted as vibration and earth rumbling instead of audible sound. Within a radius of 2 km from the factory, there were damages such as vibrations like earthquakes and earth rumbling, and sound of walls and windows.