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remagnetizing alnico speaker magnets for better speaker performance

bluesky

bluesky

Lunatic Member
I read somewhere a few years ago that 'remagnetizing alnico speaker magnets' will improve the speakers performance. It has something to do with when you play speakers with alnico magnets 'loudly', the magnets, over time, get out of 'magnetic allignment' or something like that. But, it was stated that this can be easily resolved by re-magnetising them, then they would be as good as new!

1. Have any of you guys ever re-magnetized your alnico magnets, or heard about this????
2. Did you notice any difference in sound quality of the specific alnico magnet speaker??
3. Is it worth doing if you were doing a speaker system refirbrishment? :scratch2:

As always, your help is most appreciated.
 
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i wonder if wrapping a wire around it, as in a coil, then either using a 120 volt or using battery power, would work the same way to magnetize it?
 
budgetaudio6 said:
i wonder if wrapping a wire around it, as in a coil, then either using a 120 volt or using battery power, would work the same way to magnetize it?
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Oh God, don't try this!

Magnetizers are big, heavy duty machines made just for that purpose...it takes a LOT of current to induce such a large magnetic field as required that any kind of homebrew situation is probably pretty dangerous...I don't think you could deliver anywhere near the current necessary with just regular house current...even if you used your oven or dryer outlets....I may be wrong, but I remember seeing a magnetizer once and was impressed with what a hevy duty thing it was...
 
guess im still wet behind the ears. Im remembering wrapping a nail with wire and either 120 volts or batteries to magnetize it.

This was all in elementary school.
 
When I read the short article on this, many years ago, I remember they said that just about any 'professional' speaker repair facility has the equipment to do this remagnetzing job correctly.

I was just wondering if it really makes a substantional improvement in sound quality in older vintage alnico speakers? Sounds like to me, if you have everything apart anyway, why not!!?? It does sound like it makes sense. Guess playing alnico magneted speakers loudly changes the magnetism of the speaker magnet, in a not good way, but that is a problem inherent with only 'alnico magnets'. That's all I remember about this and it just stuck in my mind. The article also said that the ONLY way this can be restored is by re-magnetizing the magnet. It would never get better all by itself and will only continue to degrade over time. Which is normal property for alnico magnets.

I do 'love the sound' of alnico magneted speakers!

Just wondering if any of you guys have any experience with this and if the speakers do sound noticably better after remagnetizing?
 
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I don't now about the speaker but the video was good.
I especially liked winding the voice coil.
Alnico guitar pickups can become de-magnetized and be re-magnetized so I guess it could happen to speakers too.
 
This is so impractical that I am unaware of anyone doing it, except perhaps JBL. The magnet pretty much has to be disassembled from the polepieces to do it and the strength is a specfic part of the speaker's recipe. With a change in magnetic field strength the speaker driver's characteristics change and you have something somewhat different from the driver's original spex. I have remagnetized some transducers without a complete teardown but that is strictly case-by-case and maximum saturation was the main criteria. Assembled speaker magnet/polepieces are something else altogether and the shorting effect of the gap would have to be overcome for starters, never mind effectively accessing the magnet's poles.
Have heard that there are supposed to be preferable differences with AlNiCo magnet speakers but given all the other variables including aging degredation I don't 'get' it and I'm a subjective as well as technical minded guy. Supposedly ceramics came to dominate mainly due to logistical difficulties with obtaining cobalt in reliable quantities. Radar and pro speakers relied on larger high-strength AlNiCo magnets, I'm sure there were other applications. Rare earth ceramics have pretty much replaced these AlNiCo apps with smaller, lighter, and more powerful pieces. Only nostalgics seem to miss it.
 
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Alnico magnets do need to be re-magnetized if they're over driven, overheated or ...dropped (yes, it really does).
Dan Wiggins used to have, what he claimed anyway, was the biggest magnetizer in the Continental US, although I can't remember how many joules it had. It was the size of a big freezer. I do know that Dan was very careful powering it up, although he seemed to like seeing how far he could make a subwoofer jump in the air when he fired it off!

Best Regards,
TerryO
 
DanO55 said:
Ouch.
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Actually Magnetizing a nail with house current and wire isnt very difficult or painful.

A switch, a light bulb(socket included) another wire in series, and using that wire to wrap around a nail.

HMMcome to think of it i dont think it would work with AC, certainly does with DC though.
 
HMMcome to think of it i dont think it would work with AC
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Just need a diode in the circuit, better yet 4 of them in a bridge configuration.

Great Plains apparently remags any driver that is sent to them for rebuilding.
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They also re-mag drivers that are sent to them just to be re-magged. :yes:

FWIW, a driver with a weak magnet will no longer be within it's T/S parameters which can affect how it acoustically aligns with the box as well as how it electrically aligns with the network.
 
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Very interesting. Now I know something about it. Hope this thread keeps going for awhile. Interesting.

Didn't know you had to take the magnet off of the speaker...disasembly and re-assembly.


I wonder how this would effect the sound quality of 40 year old alnico speakers??? As in...would it really be worth it to do this project, or just leave them alone, as is, in a speaker refirbrishment?
 
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How would you know if alnico speakers need to be re-magnitized ? Do they stop producing sound or not play as loud ?
 
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