out of curiosity, would something like this hurt a human? I assume the sound waves must be pretty powerful to put out a fire.

It's a standard subwoofer speaker/driver put in a ported enclosure, running at 30Hz, creating a particularly "fast punch" sub. The design of this would have all the same goals of a normal subwoofer: moving a bunch of air at low frequency. You can buy this sort of design to listen to music in your car [1]. It all runs on 12 volts because it's standard car audio equipment.

Subwoofers can definitely harm human ears, but definitely not human flesh. Just don't put your ear up to it.

[1] https://cadencesound.com/product/tube12vp/?srsltid=AfmBOoqdE...

There's plenty of links in Dublin comments for other instances of the tech being developed at least partially, and at least one for in-home fire suppression. Given that last one, I'm thinking it operates on the basis of resonance rather than amplitude to disrupt combustion.

Seems like a standing wave thing to halt airflow rather than "overpower with Bill & Ted's Awesomeness!".

Depending on what they have going, it might be loud, might not.