> I wonder however what would happen if there were essentially two coils, the inner voice coil, and an outer field coil that were both wired to the same amplifier power output with their polarities reversed as to provide double the push / pull in either direction?
I actually tried this some years ago. The idea was to have a "magnetless speaker"
A voice coil needs to be immersed in a pretty strong magnetic field with it's flux focused in an oval from top to bottom of the voice coil.
Two voice coils each receiving the same power level would not cause either one to attain any motion.
Even if one of these coils had a higher power level fed to it, it's still substantially too low in power to create a magnetic field to get the other coil to react. Plus the issue of not having an iron pot to focus the field.
The well designed high powered ferrite and neodymium loaded modern speakers we have on the market today are far away better than any field coil speaker could be.