From: pallison49@gmail.com   
      
    Tom Del Rosso wrote:   
   ==================   
   >   
   > AIUI you use iron cores for low frequency and ferrite for high frequency   
   > because ferrite doesn't get magnetized,   
      
   **  LOL  -  wrong.   
      
   Most loudspeakers use FERRITE magnets !   
      
      
   >  so why couldn't aluminum do the  same?   
      
   ** Or a piece of wood ?   
      
   FYI   
      
   the whole point of a core is that it DOES get magnetised.   
   And as easily as possible and with the least energy losses when cycled in each   
   direction.   
   Iron / Silicon alloys are is the only materials that do that well at low   
   frequencies.   
      
   Ferrite has very low losses at at ALL frequencies but cannot compare with iron   
   at low ones for sheer brute force.   
      
      
   ....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)