How can I produce infrasound using a bunch of piezo's?

The industrial music pioneers Throbbing Gristle reportedly created something that was capable of producing sound at frequencies below the threshold of human hearing (infrasound) by wiring together a bunch of piezo's. I'd love to do this myself, but don't currently have the time and resources to experiment myself. Any chance that there's someone out there that has replicated this? Preferably someone willing to write up an instructable?

VIRON7 years ago
If all the piezos were driven at their near ultrasound resonance but at the same time half of them were slightly lower in frequency than the other half, then they would create an infrasonic beat at the frequency that is the difference between the two ultrasonic frequencies, but I don't think it would be powerful like a big subwoofer, unless they were attached to an infrasonic resonant object which also has a nonlinear response to high frequency waves (such as an ability to double their frequency).
Grathio7 years ago
They probably didn't use standard piezo speakers since they're closer to ultrasound than infrasound. If I has to use the piezoelectric effect to create infrasound I'd probably wire up a bunch of piezoelectric motors across the surface of a very large membrane (a giant drum head) and use a master controller (say a 555 timer chip) to trigger them simultaneously.

It would probably be cheaper/easier to use solenoids or linear actuators, though their weight might interfere with the vibration of the membrane.