The most dynamic speaker you've heard...

Mapman, I haven't heard a field-coil version of the CAR Hartsfield, but it would probably surpass the "regular" version that I've heard several times over the years.

Duke
dealer/manufacturer

MBL 101E Ridiculous!! These blew my mind!

Going off tangent a bit, but field coils do open up a lot of possibilities that fixed magnets can't match. You could have active flux modulation compensation for example.

Power supplies have to be incredibly well regulated so that back EMF generated by the amp and voice coil don't cause the magnetic flux to wander.

Feild coil driver uses an electromagnet instead of a "permanent" magnet like a ceramic magnet because they're easy make or an Alnico V, or now rare earth magnets (neodymium.) Usually very costly, but I think that they're
overpriced.

dc10audio L'Instrument by a big margin! The big brand old JBL second!