It seems @wyleu fell into the tech ingredients rabbit hole, good luck friend!
Well we have tunnels to explore. . .
Transducers might make good hidden sound sources in a Haunted House setup, I wouldn’t expect a very flat frequency response in the typical random sounding board application.
Could be part of some experimental acoustic instrument whose current resonance effects the driver signal.
The Tonewood amplifier for acoustic guitars, it vibrates the body as a sounding board. it’s stuck on the back held by magnets on the inside, Some who compose on their couch find new inspiration from the added variety of sounds.
There are endless youtube videos of pros trying them for the first time.