Modelling loudspeaker magnets..

["emacoustics" <michael.wheeler@xxxxxxxx>]

Hello folks,

I'm kind of new to using FEMM, and am trying to model a loudspeaker 
coil/magnet assembly for my final year university project. I'm 
modelling to observe the effect the flux generated by the coil has on 
the permanent magnetic field. The model is really simple - one block 
of steel, one block of Neodinium, and one (and sometimes two) coils 
(which are represented by square blocks at present, though may get 
changed to circles) in the gap between them. My problem is in not 
understanding how to input data for magnets - I modelled the system 
with no current in the coil (and with no coil at all) expecting to 
see field lines between the neodinium and the steel, and saw 
nothing. When looking at material properties, there are lots of 
values for constants I don't understand, nor did I really understand 
the manual either. Can anybody point me in the right direction? The 
model is just to show that the coil affects the permanent field when 
a current runs through it, and by adding a seconc coil in antiphase 
this can reduce this problem.

Many many thanks, I'm getting desperate!

Best Wishes,

Mike Wheeler
Final Year Undergraduate, BEng Mechanical Engineering
Imperial College, London