If I want to make an object jump on screen by clapping my hands, amplitude would be the simplest to use. The other values vary widely for me.
Yes, now I remember a similar discussion with Abe-san^^; The level values after the FFT is only meaningful in a very controlled environment. A clear input from a music instrument with very clear harmonics and you can see it (according to Abe-san). But I'd agree that it is more or less very specific to a certain application.
The raw level value, that is like the sound recorder's level meter (which you also had an Etoys that takes advantage of), should be a tile and it would be more useful.
Perhaps they should not even be there unless there is an actual WorldSthethoscope connected?
Or in a normal case, it is not even necessary.
-- Yoshiki