By psichofony, did you mean cacophony?
So, what you want is something that can seperate a single voice from the background noise?
I think you need the sort of equipment that law enforcement agencies use for something like that.
I'll try to find something though.
edit--
http://www.zzounds.com/item--WAVNATIVEREST
$ 900?! Holy shit
I'll see if I can find something cheaper.