I've just come across a really interesting article, entitled 'Ghost Story: Low Frequency Illusions'. It looks at the effects of 19hz vibrations on humans - it appears that when combined with a spooky situation, it can lead people to believe they're being haunted.
It's a short and fascinating read.
Check it out: http://www.livesoundint.com/archives/20 ... ow/low.php ^_^
