Flux capacitors?, like the ones from Back-to-The-Future? lol ...
I think what it's doing is projecting a quantified amount of energy (call this the carrier) - and riding a long side this energy is the audio (or at least part of it). Similar to RF, we have a carrier and the audio modulating it, but instead of an electrical receiver, we have physical matter to do the same thing at receiving end. My guess is that, the carrier is just a huge mass of power. This thing is highly focused and can be used with incredible pinpoint accuracy. I have been standing in a crowd full of people with this thing projecting voice into my ear and no one else around me hears a thing.

(And no I'm not nuts, my psychiatrist assures me)