(Dick Pierce) wrote in message ...
(Svante) wrote in message news:hO3db.435049$Oz4.241458@rwcrnsc54...
First of all, your data is inconsistant with Leach's and also with
Lip****z and Vanderkooy's, as well as my own, where it is the
mechanism of lossy eddy current generation in the pole piece and other
moederatey conductive parts in proximity to the voice coil that is
responsible for the non-ideal behavior of the inductance.

The phenomenon we observe is that as we go higher in frequency, we
see an increase in eddy current coupling in the metal parts, which
have a fairly high ohmic loss. The result is a decrease in inductance
and an increase in resistance that pretty reliably follows a 1/sqrt(f)
for inductance and sqrt(f) for resistance.

Pardon me for responding twice, but I thought you may be interested in
seeing the actual curves. The curves are available at
http://www.tolvan.com/disected_lsp.jpg
As I said I observe the same as you do, the red line is from the
disected loudspeaker, without any iron or magnet present, the black
curve is the impedance of a normal element of the same brand and
model, and the green dashed line is modelled data with a "n" value of
0.67. The model also includes the mechanical resonance, as you may
see. I think we agree that there is a huge difference between the
black and the red curves.
The model fitting was done manually by adjusting the parameters of the
model until the curve fitted well. I think the match between the green
and the black line is is pretty good. (Don't look to carefully at the
phase towards high frequencies, my sound card makes the phase values a
bit too low there)