Precis som Raidho verkar man jobba på lite nya lösningar. Specialkabinett osv.

Element utan järni motorsystemet.

https://www.audioshark.org/speakers-10/ ... age16.html
The Børresen magnet system is totally unique and very different from anything else on the market. Having worked with driver designs for quite many years, we have seen that the fundamental structure of magnet systems haven’t changed since the loudspeaker driver was invented. Iron is used to concentrate the magnetic flux in a narrow gap the the voice coil is located. Iron is good for concentration of flux, but also poses some challenging issues when it comes to the voice coil parameters. The parameters simply change with VC position, leading to iron distortion.
The Børresen magnet motor is uniquely designed without the use of iron what so ever, instead 4 opposing neodymium ring magnets are used to squeeze the flux lines together over two solid copper discs that then act like pole pieces.
The Børresen magnet system has a high flux of 1.1 Tesla and the solid copper pole rings act as very effective heat sinks giving the driver very high power handling.
The copper pole rings also reduce voice coil inductance to a very very low value of 0.04 mH (less than 10% of normal drivers)
The extremely low induction gives the driver some very desirable attributes. Two which are very good and very desirable. Lower induction means a faster driver, with no lag and thus a very detailed presentation. Lower induction also means less resonance impedance variation, meaning less phase angles and impedance variation for the driving amplifier, and also less impedance rise over system resonances, leading to a much smoother and less boomy base presentation. Bass performance becomes very tight and well focused. The Børresen magnet system is patent pending.
https://parttimeaudiophile.com/2018/11/ ... -launches/