Hi Anunnaki - Thanks, I was getting confused with the variety available and the new terminology. I read an article by Dr Clark's organisation about trying to make fool-proof zappers due to the difficulty of detecting the variation of sounds - is this the distinction you were making - ie. that the FSAN to some extent made this process of interpretation easier?
I imagine there aren't, but are there any other books out there, apart from Dr Clark's, about choosing and using zappers?
Many thanks again!