[Petronski]

Note to self: build and deploy a 7Hz emitter. (Contact eno_ with specs and instuctions.)

[eno_]

It could actually be quite challenging. A normal loudspeaker would be horribly inefficient at that frequency. Even a horn would be troublesome. So the question is if it is possible to make a really small hydraulic emitter, like a small whistle or organ pipe tuned to 7hz. Which gets you into the physics of hydraulic emitters smaller than the wavelength.

[MD_Willington_1976]

And at the other end of the spectrum the Russians used to use higher frequencyies against the US embassy in the USSR, they did quite a bit of experimenting with it on how it could be used to motive people and to cause problems...the us military has been playing with HF weapons too, actually you can focus beams of HF at incoming devices like missiles and scramble their electronic brains...

http://www.house.gov/jec/hearings/02-25-8h.htm

http://liun.hektik.org/hightech/herf/ISTAS.htm

Have fun...put your foil hat on too

MD