"Bob Cain" wrote in message

Arny Krueger wrote:

I just ask that you draw no conclusions from a system that
contains measurable non-linearity in the transducer itself.


I think that's being too restrictive. We have at least two ways to
distinguish AM from FM. The fact that we're finding so much AM is
probably a guide to the most practical answer.

Arny, when you start mixing distributed non-linearities such
as that in the surround, that of cone distortion, that of
the magnetic circuit, etc. It is not generally possible to
describe the resulting form of distortion.

What, whether it is AM or FM or what proportion of which?

Sources don't matter, all that matter is a clean enough signal to analyze.

It most likely
involves recursion and thus results in chaotic effects. I
can see no reason why FM cannot occur as a consequence of
these mixed factors. Just about any form of non-linearity
can result from them.

Lets go down your list:

(1) that in the surround - doesn't matter where the Doppler comes from,
just that it is.
(2) that of cone distortion - doesn't matter where the Doppler comes from,
just that it is.
(3) the magnetic circuit - not moving, so it can't cause Doppler


In fact, when I simulated a simple model of the described
effect, the distortion produced was chaotic and broadband,
not isolated spectral lines.

We get pretty clean isolated spectral lines from real-world measurements.
Guess what that says about the simulation?

Until that can be done the effect described remains hypothetical from an
experimental standpoint.

We don't need a working theory to have believable experimental results.