[AliAdams]

Take this as a fairly baseless comment but my reading of analyses around the original incident seemed to be saying that it was closer to microwaves than sonic waves. The side effect of the exposure was that targets had the illusion of hearing sound.

[tomalpha]

I too thought that - especially given that it's (I think) a well known phenomemon: https://en.wikipedia.org/wiki/Microwave_auditory_effect