In a vacuum tube, nobody can hear you scream.

[Magpie]

My hippy sister in CA goes on about them. Happening to have two signal generators
lying about, I tried it. Nice effect, but didn't see God(s). I guess my brainwaves weren't feeling
entrainable that day. Ask me about bat (the mammal) detectors. Have done what you might
call a bit of psychoacoustisizing there (single note cords).

... but I digress...
I'm more than willing to hear ( ) you ranting about binaural beats. Convince me.

Well I wasn't really being serious but... Tell your sister no. It's not true. I'm fairly certain that it had been disproved because all of the results where it was shown to work were called into question when it was pointed out that headphones were used and because headphones have got magnets inside of them then they would affect whatever equipment was used to detect the brain waves. I think that they tried the test again using headphones without magnets and the same results weren't achieved.

The whole concept seems a bit bizarre in the first place because essentially we are talking about two notes that are slightly out of tune with each other. In some sense it's not real and is only a perceived phenomenon due to the fact that the brain can't process two tones that are so close to eachother. Although saying it's not real and only perceived is a bit hard to comprehend when the effect is very obvious and as well as being heard the fluctuation can be felt in the ear drums. At one point in time I would have said that the only real use for binaural beats was in helping musicians to tune instruments, which is what I've always used it for, however after recently reading a book about acoustic weapons it would seem that various governments around the world have realised that the phenomenon can be used and has been used to disperse crowds. It makes sense that it would work because even at low volume it can be quite distracting and annoying but when used at much higher volumes I can imagine it would be very disorientating. When I read it my first thought was "bastards", how can they take something so simple and natural and turn it into a weapon. On the other hand faced with a crowd of people who were deaf in one ear their weapon would be hopeless. But out of all the possibilities that armies have looked at for acoustic weapons it is one of the milder ones that are possible. The common 'acoustic deterrent' that they've been using for years is to play a noise that is of a frequency that only under 16's can hear. They play it at train stations and shopping malls to stop teenagers loitering. However teenagers have turned the tables and they ingeniously use it as a ring tone on their mobiles that teachers can't hear.

Bats??? Sounds interesting. I know a little bit about how they use Doppler shift but probably not enough. Any mammal that has evolved to have the ability to fly is definitely worthy of respect. In fact they are the only mammal that has evolved to have the ability to fly (flying squirrels don't fly they glide). Whereas any mammal that spent a long time making little blindfolds for bats so they could prove that bats use sonar is probably a bit mad as well as slightly genius.

I'm all ears.