Diptyque Planar magnetic speaker - Motor design "PPBM"

I was wondering what PPBM (Push Pull Bipolar Magnet) was, and i am pretty sure i've seen this before. but anyhow i thought i model it in FEMM see what it does, compared to a regular push pull.

let me know if you ever seen a none Bipolar magnet (a bare magnet). if so you get a beer from me !

i said cm at 8:45 its of course mm :)