I can feel there is good stuff going down here.
My own meager contribution would be to suggest that you sweep the frequency range from around 77kHz to around 800kHz (the parasite bandwidth). Repeated as a series of rising (and falling?) frequency pulses.
If you could hear this it would sound like a rising pitch police siren wailing up and down in frequency.
How easy it would be to do this? I don't know, but someone would point in the right direction I am sure.
The above link might be a starting point for some thought.