<crap snipped>

Ultrasonics my arse.

It's all done by pitch and tone of voice and I'm not talking about Frank
Herbert's Dune books. I realised it long before I ever read those.

Why'dya think the BBC changed the Cybermen's extremely creepy
randomly-pitched speech to the simple buzzers that people who'd lost their
vocal chords used in those days? It might have given the game away!

And have you ever compared Thatcher's tone of voice with that of a
professional hypnotist?

If you're going to troll mind control, at least choose methods that are a
bit more likely than firing sound at people that's so high pitched they
can't hear it! - even when it's modulated.

And to save any more crap - I used to work in ultrasonics, have a large
collection of crystals of different frequencies, and no way can I find a
method by which their sound could be made to control anyone's mind!