Hi Canie:

I did not mean to imply that you thought it was a sure concept or anything.

It seems that more people see it as a curiousity...and clearly without any scientific foundation (as you probably know...)

Regarding instruments...there may be complexity in the physics of it which are better captured with a human-in-the-loop (i.e. through a sensitive)...with the future possibility of transporting the knowledge about it to instruments mated to a computer based recognition systems (as one possibility).

A very curious attribute is the "one ear" or the "other" of these "tones" in alot of cases.

The "nods" that Petra mentions also suggests some form of nervous system/brain/perception event (which may or may not be easily captured by instrument). Clearly, to me, the front end effort in doing any type of study in this area is to keep the study close to earth sensitives initially (while possibly keeping an eye on instruments secondarily). After exhaustively extracting this info. and finding any correlations then a move towards instruments might be the next step.

It may also be true that there's a type of instrument out there which should/could be used but is not...(and which sensitives may correlate well with)...guess time will tell.