What is a resonator?

There is the concept of the resonator in the phantasm movie. It is quite interesting even if I say so. A resonator is similar to a tuning fork in some ways. I believe an HDR creates scalar waves. Mostly, this is just a theory, but they cause a similar noise. Perhaps the person who made the movie had seen Astral Hell. That is what the smoke place is similar to, but then again - it could be a coincidence if you know what I mean.