Matterhorn
Matterhorn Deets

A commenter from our previous humongous woofer post points out another contender for biggest-sub-ever – Enter(literally) the Matterhorn –

The most powerful sub ever created. It was born out of a
military request and is housed in a 20′ x 8′ x 8′ shipping container.
40 drivers, 40 kwatts of self powered and built in generator to boot.

Hoo-aah! – Matterhorn