[JohnR]

Why do drivers with Alnico magnets sound better? (I assume that's the case, give the price difference!)

Also, what's the subjective nature of the difference? Does it apply only to fullrange drivers, and why?

Just curious, you see...

[FullRangeMan]

Good question ! 
I also want to know about it. Alnico magnet need a different, special cone/VC project from the ferrite magnet.
What I now is a Alnico magnet lost 50 to 60 % of the magnet power in aroud 10 to 15 years, and need to be electrically recharged in a special machine.
In the Fertin site they said something about it. My knowledge ends here. I think the Alnico magnet give much Harmonics to the music that are please to the human hear, just like the tubes.
I wonder if the normal ferrite magnet does not lose its strength with the years? 
Regards,

[richidoo]

AlNiCo can be magnetized to a much higher flux than the standard ceramic magnets (ferrites) used in most speaker motors. That increases the acceleration of the driver and perceived detail. Isotropic AlNiCos are the oldest of the high energy magnet technologies, from the 50s. They will lose magnetism over time, accelerated with moderate heat. Modern anisotrpoic Alnicos are harder to demag, and are more powerful. Neodymium Iron Boron is the state of the art magnetic material now. It will not demag and is extremely powerful, and expensive. AlNiCo won't rust like Neo. 

[JohnR]

AlNiCo can be magnetized to a much higher flux than the standard ceramic magnets (ferrites) used in most speaker motors. That increases the acceleration of the driver and perceived detail.

There must be more to it than flux density. The Supravox 15" ferrite magnet drivers have higher flux density than the Alnico ones, for example. (For the other drivers, it seems Alnico is about 50% higher, give or take.)

One claim I found is that the driver supposedly compresses softer at high excursion - but if modern Alnicos don't demagnetize, then that doesn't seem to apply - ? I'm finding it a bit hard to separate current information from historical in what I've read.

[FullRangeMan]

There must be more to it than flux density. The Supravox 15" ferrite magnet drivers have higher flux density than the Alnico ones, for example. (For the other drivers, it seems Alnico is about 50% higher, give or take.)

Only a strong, big magnet dont make a powerful speaker motor. All depend on the magnetic density flux in the gap, where the voice coil walk.
If the gap in too large the VC do not receive much magnetic stregth etc...

[JLM]

My Fostex F200A drivers use massive AlNiCo magnets and sound wonderful.  Very rich, clear, tonal, yet detailed with incredibly deep bass.  These definitely ain't your typical higher efficiency Fostex drivers (most of which sound thin and lack deep bass).  With the EnABLE treatments, Bud Purvine says they are as good as any driver in the world.

Sorry, I shopped for these about 6 years ago now and can't recall the advantages of AlNiCo.

[Bemopti123]

I am not apt to describe the technicalities of what separates Alnico speakers from standard magnet ones, but one thing is for sure, most Alnico speakers I have heard have this ravishing midrange that in the case of the F200As that JLM describe sound "robust" while the equivalent drivers with a different magnets sound thin comparison.  Furthermore, instead of sounding sluggish due to a "fuller" sound, the Alnico speakers in general, at least for me, sound quite accurate, does not "gloss over" cues as they were recorded and reproduced. 

[Alwayswantmore]

This is something I helped write for Omega's site... http://www.omegaloudspeakers.com/about/alnico-magnets

It is not technical, but does speak to sonic advantages.

I've owned Compact Hemps (ferrite.), and now have Super 6 Monitors (Alnico). The Super 6 sounds better in every way. And though the driver is smaller, even the bass on the 6 sounds better (significantly improved texture, tone and layers - without a perceived loss of frequency response or punch).

I believe the reason Alnicos sound better is not tied directly to the size or power of the magnet, but rather to Alnico's magnetic qualities being inherently better at accurately responding to the input signal.

[JoshK]

Some things have been said before, but there are a few things missing it seems.

Alnico is suppose to have better flux stability that is suppose to lead to better BL linearity.  Also, the permeability of Alnico is higher than Ferrite.  With modern drivers, ceramic motors are often aided with shorting rings (you can read what all they do, I couldn't give a good synapse) which greatly increases their performance.  Alnico motors don't need shorting rings because they are already there (I think it is due to permiability).  Neo motors are in between in this manner.

John Janowitz of AES speakers has written quite a bit on this subject on diyAudio in the Beyond the Ariel thread but it will be tough to find since it is buried in that thread.  He sells drivers and has his beliefs but he also describes the differences in technology succinctly.

[floobydust]

 One good example of the difference in sound quality is comparing the Fostex FX120 and F120A drivers. For practical purposes, these two drivers are almost identical sans the magnetic section, the FX using ceramic and the F using AlNiCo.

 As for the cost differential, the latter is more than double the price. As well known, AlNiCo is named from the 3 main elements it's made from, Aluminum, Nickel and Cobalt. Nickel prices have gone up over the years and even worse, Cobalt prices have shot up. According to an article I read sometime ago, most of the world's remaining Cobalt supply was on the other side of the old "iron curtain".

 The old saying still holds true... location, location, location.

 Regards, KM

[S Clark]

The leaders in production are Australia, Dem. Rep. of Congo, and Russia, with Canada and Zambia producing also.  It's enough of a mix to keep prices from being fixed easily.
http://www.mapsofworld.com/minerals/world-cobalt-producers.html