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

@devinplombier 

Understood, but what makes Field Coil better than permanent magnet. I saw a video where this driver has a second “Reverse” Wizzer cone under the main cone and that improved the sound, but…
 

Thanks.

@curiousjim wrote:

Thank you for the link. I’ve probably watched a dozen videos so far and I understand how field coil works, but I still don’t understand the why. Before we were all born, a radio that produced 1/2 watt was amazing, but watts are not a problem anymore.  

Back then few tube wattages were more efficiently turned into acoustic output with larger and typically horn-loaded, very efficient speakers. Watts in abundance is now easy to come by, yes, but more power is turned into more heat in the voice coils and passive crossovers of the smaller and much less efficient speakers of today, and thus heat dissipation becomes a challenge and the new problem; thermal compression is said to enter the picture already at 1/8 of a driver’s rated power handling, and as a dynamic phenomena thermal modulation is believed to have its effect in stunting the transients with very short heat built-ups and rise in resistance in the voice coils.

More efficient speakers have lesser issues here in needing less power for a given SPL, and active configuration is a way to aid an amp’s ability to control the cone of a driver more precisely - not wholly unlike the advantage of an electromagnet and its better control over the cone movement. 

The why of electromagnets back then was necessity and doing what needed to be done; the why of and demand for them now is better sound. 

Someone said that field coil speakers were better because the power could be adjusted.  I didn’t find anything about that at all.  I guess if you are looking for a Dipole full range driver maybe’s?

Electromagnets are inherently better due to their ability to control the moving mass much more precisely, which is the main takeaway, while adjusting the voltage of the DC power supply lends the opportunity to vary the magnet flux density and thereby tune the overall character/tonality of the sound. 

I’m still having trouble with this strong magnet vs that strong magnet.  Either way it seems to be a more expensive way to build a driver.

More expensive, heavier, larger, generating heat, the need for a (quality) DC power supply, yes, but really it’s about this weaker permanent magnet vs. that very powerful electromagnet and all that entails. They’re a tougher sell for sure, but if the benchmark is better sound followed by will to get there, they make sense. 

The loudspeaker industry moved away from electromagnet drivers to permanent magnet drivers for one reason. Permanent magnet drivers are cheaper to manufactuer. Which type of magnet sounded better, did not matter to the industry. 

Mike

The ideal magnet is not as easy as selecting the most powerful magnet.  You can make permanent magnets speakers with way more flux density but it would not sound good.  Have you heard speakers with “weak” alnico magnets?  Some of the best drivers employ such magnets because they sound good.

I don’t field coil speakers are inherently better.  I’ve heard compression drivers that are pretty much identical except one has field coil magnets and others have permanent magnets.  For example the Western Electric 555 driver (field coil) and the Westrex permanent magnets version both sound good.  I would take the Westrex because it is far easier to use.  Some YL clones of the 555 using permanent magnets sound great too.

I’ve enjoyed field coil drivers with fixed voltage supplies and those that allow for adjusting the voltage.  The sound can be changed by changing the voltage and I don’t think this is necessarily good—I don’t like having to fiddle with adjusting things as the speakers warm up.

@deep_333 

I just wanted to apologize.  I feel like I’ve hijacked your thread and I really did not mean to.

All the best.

Jim