Just a follow up on this, when I asked a similar question on uk.relgion.pagan
they did mention something called infra sound being linked to hauntings.

This was one of the links I came up with.
http://www.100megsfree4.com/farshores/p_ghost7.htm
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Rhiannon
http://www.livejournal.com/users/rhiannon_s/
Q: how many witches does it take to change a lightbulb?
A: depends on what you want it changed into!