Infrasound???

Recently I ran across the term "infrasound" and naturally had to do some research. What I found was quite fascinating. Infrasound is a range of frequencies below that of human hearing. Infrasound can in some cases explain ghosts (the resonant frequency of your eyes is 18hz) as well as the spine chilling feelings that accompany them. Animals use infrasound for communication and may also induce a sense of discomfort or disorientation in man in cases of tigers and lions. It can also be used as a weapon. Unfortuantely, in the quest for the lowest and most powerful bass from car stereos it is becoming possible to create infrasound with exotic car audio equipment which may be more detrimental than people realize. Just thought I would throw this out as an interesting audio topic. Check it out.