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-   -   What happened to the alnicos? (http://www.diyaudio.com/forums/full-range/230320-what-happened-alnicos.html)

Guitarski 18th February 2013 10:43 PM

What happened to the alnicos?
 
Hi,

I read a thread, from 2010 I think it was, that overnight alnico speakers almost doubled in price. Does anyone happen to know what caused that? If I have understood the info on the web correctly, cobalt isn't overly expensive at the moment.

Thanks/regards
- Guitarski
Http://rocking.mobi

Scottmoose 18th February 2013 11:05 PM

You're probably thinking of Neodymium rather than AlNiCo. Prices for that rocketed because China have what amounts to a monopoly of the production of such magnets at present, and IIRC they announced they would be limiting exports. Which caused a bit of an international fuss.

Guitarski 18th February 2013 11:15 PM

I'm really mean alnico. If you look at Eminence for instance, the alnicos, like Red Fang, Commonwealth (guitar speakers) are quite a bit more expensive that their Neo (Tonkerlite). There was a conversation from 2010 that mentioned the Red Fang going from $170 to $260 (or something) literally overnight.

Thanks/regards
- Guitarski
Http://rocking.mobi

Bare 19th February 2013 02:28 AM

Could be like Gasoline the price fluctuates with speculation?
Although the Jump was last month and it has receeded :-)
London Metal Exchange: Cobalt
Sad part is that Alnico performs far better than Neo in speaker motors. Neo is Very temp sensitive.. at 100C most all Neo variants demagnetises.. Not good. But then it's beyond normal for speaker motors to get to even that level of overheat.. or not?
Besides Neo self oxidizes into toxic powder as soon as the encasing plating fails.. typically far Sooner rather than later. Even I have few examples of that self destruction. Safely, in sealed containers.
Whereas the Cobalt alloy Alnico has a 2000 year Utterly stable Gauss with a 2000 year projected Half Life . Also has ~600+ Celcius Currie point and NEVER actually needs a remag.
(Unless owned by someone who has no clue and the 'servicing' is by some inept disreputable )

Interesting material indeed.. even beyond strategic (Nuclear warhead) uses.

Alniico is one of the time proven better motor components of any worth owning speaker.
Likely some makers are starting to charge even more than their costs :-).
Profit is where they can squeeze / find it.. increasingly the way of the world.
Too much? don't Buy :-)

xrk971 19th February 2013 03:11 AM

I don't understand the fascination with alnico - a 1940's technology that is 10x less powerful than state of the art rare earth neodymium iron boron (NIB) magnets. Is it just the 'branding' and certain manufacturers carry it for this mystique? What is the advantage of alnico over NIB, or neodymium as people refer to them?

Guitarski 19th February 2013 08:33 AM

@Bare
I read somewhere that alnico magnets costs $44 / Kg, so the price may be in the production, but why the overnight hike? If it has a military angle, as too many things do nowadays, then what happened in 2010, just curious.
I didn't even know that neodynium was so unstable, that's not the bang for buck I'm looking for.
@xrk
Alnico smooths out the sound of a distorted guitar and gives it a quick attack. Many people like the "British" sound, which is spikey by definition, as opposed to smooth. Therefore alnicos with a British voicing, like the above-mentioned, are actually a contradiction.

Thanks/regards
- Guitarski
Http://rocking.mobi

mondogenerator 19th February 2013 08:58 AM

many forms of NdFeB mags exist, some of which withstand temperature far better, such as those used in permanent magnet wind generators (Which i was involved in testing some 5 years ago). As with many things, you get what you pay for, although you can pay too much (poor neo can be found, just as poor alnico and ferrite can also be found, Whatever material quality costs. Samarium cobalt seems to have fallen from favour, i have no idea why.

xrk971 19th February 2013 09:27 AM

There are old threads on this topic of alnico vs neodymium vs ferrite.

http://www.diyaudio.com/forums/full-...ke-alnico.html

I am of the belief that it all comes down to field strength. If you design motors to have same B field in magnetic gap, the voice coil knows no different. Different magnet materials call for different physical dimensions. Good design technique should be used to provide adequate cooling to stabilize temperatures but the fundamental physics of Lorentz's law doesn't care about what material is in the equation: Force = q (v X B), where q is fundamental charge of electron, v is the velocity of electron in wire loop, and B is magnetic field. The magnetic field B is all that shows up, not any other 'intrinsic' property of the material. When arguments for the sound quality of any component in a system refer to subjective descriptions, it needs to have physical basis otherwise it becomes similar to arguments of why audiophile grade speaker wires are better than cheap lamp cord, or why Teflon insulation is better than PVC insulation on audio (not RF) signals, etc. I am not saying that there is no difference in the sound, of course there is, but is the difference really due to the magnet material? As an earlier post in the referenced thread, it may come down to manufacturers giving better build quality and fit/finish and tolerance in their high end premium 'alnico' systems rather than any difference in the actual material if the B value was held fixed. A design that provides identical B field strengths, there should be no difference as far as the physics are concerned.

chris661 19th February 2013 09:42 AM

Quote:

Originally Posted by xrk971 (Post 3376221)

I am of the belief that it all comes down to field strength. If you design motors to have same B field in magnetic gap, the voice coil knows no different.

Not so.

Think about the relative conductivities of different magnets, and what happens when current flows through a voice coil.

Guitarski 19th February 2013 09:57 AM

I'm no physicist, but if you look at this quantum mechanically, don't different materials result in different potentials in the wave function, resulting in a different output of current?
:confused:

Thanks/regards
- Guitarski
rocking.mobi


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