Andrew Jones - New Company, New Speaker - Field Coil Concentric

@curiousjim 

In the old days, permanent magnets first didn’t exist, then they were very expensive (Alnico). Electromagnets were economical in comparison, so everyone used them.

In the 50s cheap ferrite magnets displaced electromagnets. Field coil drivers pretty much vanished from the face of the earth, until their recent reincarnation as luxury / boutique item.

Yup,

Permanent magnets are cheaper and don’t have the extra complication of power supplies.  Also the electromagnets produce a lot of heat so they cannot be enclosed in small boxes.  The market favored smaller speakers, particularly after stereo demanded two speakers.  

Wolf Von Langa Sons are amazing sounding field coil speakers.  I’ve had mine for over two years and they are wonderful sounding.  List price is  $17,900. True full range speakers that are two way, smaller size, not too heavy and 94-95db efficient. Use as little as 6 watts or nice SS if you like.   

Focal integrated Field Coil  drivers in their latest revision of the Utopia 'EM' models. The EM standing for ElectroMagnet.

https://www.focal.com/catalog/high-fidelity-speakers/home-speakers/utopia-iii-evo

@curiousjim wrote:

please explain.

Perhaps this video with Ken Songer of Songer Audio would be illuminating on the traits of (and a bit of history on) field coil drivers. I'm not affiliated with Mr. Songer's products nor have I heard them, but while it's a video on his speakers and the specifics of his driver it starts about by explaining a bit on electromagnets and their advantages over permanent magnets.