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(Rant warning!)What's the fuss over alnico?

frommerstop

frommerstop

Super Member
I know this will ruffle some feathers, but I think I have pretty good hearing, a good grasp of physics, and quite a bit of first hand experience with speakers, but I'm at a loss to explain why so many people are enamored with alnico magnets. I can't hear any difference between a driver with one type of magnet over any other... assuming the magnetic field is similar. It's not like alnico magnets couldn't be employed in modern speakers, yet (almost) no one does. That alone seems an interesting indictment, after all, if you were a, say Wilson Audio, or such, why wouldn't you be using these "magic" magnets in your drivers? I'm not a metallurgist, or expert in magnetic fields, but from what little I can gather they are no stronger, nor long of life than several options available today.
So my question, buried in this rant, is if anyone can explain why some people seem so determined to press this "alnico superiority"?
 
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frommerstop said:
I know this will ruffle some feathers, but I think I have pretty good hearing, a good grasp of physics, and quite a bit of first hand experience with speakers, but I'm at a loss to explain why so many people are enamored with alnico magnets. I can't hear any difference between a driver with one type of magnet over any other... assuming the magnetic field is similar. It's not like alnico magnets couldn't be employed in modern speakers, yet (almost) no one does. That alone seems an interesting indictment, after all, if you were a, say Wilson Audio, or such, why wouldn't you be using these "magic" magnets in your drivers? I'm not a metallurgist, or expert in magnetic fields, but from what little I can gather they are no stronger, nor long of life than several options available today.
So my question, buried in this rant, is if anyone can explain why some people seem so determined to press this "alnico superiority"?
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I'm one who solidly agrees with you. I've never been able to detect any difference. I have L88 speakers, with the infamous 123a driver (an excellent driver to be sure) and the only differences I detect I attribute TOTALLY to the cone design and construction. This is not to say that the VC design and other things don't play a roll, but if you swapped out the cone only, you would most certainly change the characteristics of that driver. Period. At one time AlNico was a very viable solution, but times have changed and other magnets are used that not only function better, but are less susceptible to demag due to jarring, severe loads (high wattage) etc.
 
I'm interested to hear the replies of those much more knowledgeable than myself, but I would guess it's not so much a comparison against what technology is available today but rather a comparison against the alternative magnet technology that was available at the time.
 
From an electrical standpoint, the size of alnicos may be different compared to neodymium magnets...

from what i recall, neodymium magnets are way more compact, allowing for the ubiquitus headphones made for the first walkman...before that, magnets (im only assuming alnicos are in some older phones) were big in headphones and not as protable..

more magnetism for the space is about it really...

tomlinmgt said:
I'm interested to hear the replies of those much more knowledgeable than myself, but I would guess it's not so much a comparison against what technology is available today but rather a comparison against the alternative magnet technology that was available at the time.
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beat me to it Tom..
 
The magnetic field of alnico IS different from that of ferrite, neodymium, etc. So it does cause the motor to act differently than the others, but there is nothing to say it it is superior than the others. It just costs more to make and has fallen out of favour by the manufacturers because of it. Oddly, I can easily hear the differences between an alnico and ceramic guitar pickup.
 
Everything imparts a "sound" and the magnet type might also. As a former performing guitar player and mature sound engineer I know the tube amp guitar purists insist on tube amps and alnico drivers. BUT I agree with you. If they were a special sauce you would for sure see the top manufacturers all using them. I mean it is not like cost is an issue with 20K speakers. I think there is a possibility they impart a slightly different kind of magnetic field and may in fact have some sort of effect on the sound but also think there is about a million other variables in speaker design than also impart as much or more influence on sound as the magnet material. Just like tube amps and SS amps both provide wattage to driver speakers they go about it in different ways and the end result can vary. BUT also like that amp example there is excellent tube and SS amps and crap ones. IMHO it is far more about design and implementation than it is about magnet material. I'm sure there are piles of CRAP speakers using alnico drivers and good ones too. I for one do not buy into this alnico love but have heard many alnico drivers i like all the same.
 
The woofers in my Pioneer CS-44's are Alnico, and those woofers suck, so yeah, it doesn't guarantee anything at all.
 
Listening to them side-by-side, I prefer the sound of ceramic-magnet Bozak B199s to the Alnico version. Bass is a bit tighter.
 
There is well informed discussion of this on the forum at the Lansing Heritage site, here's the way I understand it. JBL did have problems switching from Alnico to ferrite with their woofers but the sources of the problems were identified and solved. The problem was increased distortion at long excursions due to more force in one direction than the other.

It seems compression drivers and short stroking woofers using short coils in long gaps didn't have the problems.

I never heard a difference in compression drivers I'd attribute to magnet material. All the Altec woofers I owned were Alnicos and I never used the later ferrites, I can't compare. I've owned both Alnico and ferrite JBL woofers and all sounded great.
 
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I don't think there's really much point in discussing it in a general fashion, fuss or not, because it comes down to very specific specifics. AFAIK, an engineer can swap one material for another in such a way as to make a driver that performs exactly the same, if they really want to. Maybe thermal-related characteristics would still end up a little different in the end. I don't know, but that would still not give you an "A > B in general" answer. My point is, unless you take a driver design and get some people that really know how to make drivers and say "what's the best magnet to use here and why?", you might as well be discussing different colors of baffle paint. That's my take.

As for people that are "enamored" with alnico, I think that given the details, you could find much more significant common characteristics than magnet types among the speakers they love.
 
Alnico's have a softer warmer sound than ceramics. Altec 515's. JBL's and EV 15 and 18 inch woofers the difference is quite obvious. Altec and JBL changed their cone materials to make musicians happy when all the scuffle was going on. Sales dropped and Alnicos were collected and valued highly. I have Bozak woofers that are Alnico and run them bi-amped in parallel using amps with high dampening factors and large hook up wire to clean them up. There is an area around the 150 hz octave that is just cleaner with the ceramic magnets.
 
Altec and JBL made the switch from alnico to ferrite when a world wide cobalt shortage forced the change(and re-coning really became popular). Any "pro" working SR at that time will tell you that the very first ferrite motored woofers more or less sucked compared to their refined alnico predecessors. The manufacturers were aware of this "suckage" and quickly went to work on revisions that would effectively make the new ferrite motors emulate the sound of their alnico predecessors. Engineering quickly caught up with the new magnet material. There have been and continue to be many excellent drivers made with other than alnico magnets.

IMO, a lot of the love for alnico comes from a close association with those top shelf drivers that were meticulously engineered and perfected during the alnico era such as the JBL D130, D140, 150-4C, 175, 375, 075 Altec 288, 515, 604duplex, etc..

Those of us who covet these treasures don't do so because they're alnico. We covet these drivers because they're "that good". If somebody made a driver "that good" out of cowshit, we'd covet that too.:yes:
 
bowtie427ss said:
Altec and JBL made the switch from alnico to ferrite when a world wide cobalt shortage forced the change(and re-coning really became popular). Any "pro" working SR at that time will tell you that the very first ferrite motored woofers more or less sucked compared to their refined alnico predecessors. The manufacturers were aware of this "suckage" and quickly went to work on revisions that would effectively make the new ferrite motors emulate the sound of their alnico predecessors. Engineering quickly caught up with the new magnet material. There have been and continue to be many excellent drivers made with other than alnico magnets.

IMO, a lot of the love for alnico comes from a close association with those top shelf drivers that were meticulously engineered and perfected during the alnico era such as the JBL D130, D140, 150-4C, 175, 375, 075 Altec 288, 515, 604duplex, etc..

Those of us who covet these treasures don't do so because they're alnico. We covet these drivers because they're "that good". If somebody made a driver "that good" out of cowshit, we'd covet that too.:yes:
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Which bolsters my points about VC, cone material, cone shape, spider design, etc. It's an all encompassing thing. For years drag racers said Fuel Injection would NEVER work correctly in drag racing. So much for that mentality. Bowtie hits the nail on the head. There is always lots of follow-up research that must take place after something is introduced. So naturally early entries into the market won't fare well. People should take a look at the R&D budget of some of these bigger name speaker companies, not to mention the testing facilities with anechoic chambers, etc. It does tend to be rocket science at times.
 
IIRC alinco magnets are more temperature stable than ceramic or ferrite, so if you are running high power the magnetic field would not fade due to the heat generated in the motor.
 
Rick Vestal said:
If I recall, alnico will degrade over time as well...
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A re-builder once told me that the majority of the loss(up to 2%) will occur within the first months of initially being charged, and that additional losses occur more slowly than our natural loss of hearing. This was said of the typical alnico motor. But we always have to recognize that there are exceptions out there. Greg Timbers mentions(in the LH thread) a model or two from JBL that were easily partially discharged while the vast majority remain pretty stable over a normal lifespan.

I'm not convinced the engineers who originally designed those alnico drivers ever imagined we'd still be listening to them today, or holding some in such high regard.
 
I appreciate all the good feedback, I was a bit afraid it might become something of a pissing contest. I don't have anything against, or for any magnet type, as long as the speakers sound good. I've just read a lot of comments about a speaker sounding better because of alnicos, or how "you should check - you may have ALNICOs in there!", that sort of thing.

I'm also wondering if some of the reason for their popularity isn't that those magnets are starting to age, and with weakening fields, the speakers are sounding a little more "full & warm" simply because they are now a little more susceptible to overrun. Of course, I do also understand that the speakers with them were also made in a time when voicing preferences were much different than they are now. "Full bodied sound" has given way to "razor sharp detail & pinpoint imaging".
 
Timbers says that Alnico woofers with short coils in long gaps are the most stable, that would describe such Altecs as the 515 and 416.

The late John Eargle asserted that the improved JBL ferrite woofers such as the 2226 were far superior to the old Alnico JBL woofers. Eargle was an engineer at JBL and a very accomplished recording engineer to boot. The 4430 was Eargle's baby. His book "The Loudspeaker Handbook" is very interesting reading and can make one reconsider long held ideas. People with an interest in this stuff should also read Harry Olson's "Acoustical Engineering", Olson knew damned near everything. Indeed one sees speaker builders today claiming new notions that are right there in Olson.

Although Olson did get one thing wrong, when he wrote the book he thought full range electrostats weren't possible.
 
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JBL has recently gone back to Alnico in some of their TOTL home drivers like the 1500AL, 1501AL(-1, -2) and such.
 
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