neodymium speakers ?

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Greetings,

Anybody know anything about neodymium speakers?

So far I've understood that a neodymium speaker is a speaker that uses
Neodymium Iron Boron (NIB) as the material for the magnet. NIB is a very
strong permanent magnet.

My question is, whats the benefit? efficiency? cost? weight?

I'm taking a guess and thinking it's about power/weight, ie more power for
less magnet volume...but this would have to balance with quality of the coils.
Could also have to do with longer life span, neodymium holding the imprinted
field longer then normal magnetic materials?
 
Look, I'm not an expert on this, but I read recently that while being powerful for their weight they can lose their strength when heated too much. Which may be a problem when used in cars where they hold some appeal to car-audio designers simply because of their low mass. There'll be others with more magnetic 'knowhow' than me that may clarify/expand on this.
 
All other things being equal; a voice coil can develop more force in the presence of a stronger magnetic field.

There are million ways you could comprimise things; probably the best outcome is reduced thermal stress in the voice coil when compared to a non NIB speaker at equal volume.

:)
 
I've just built my first set of neodymium speakers, all I can say is that they are extremely light and powerful. the 12" PA (SPL 97db) 200w RMS driver is much lighter than say a 8" (89 db) 80 w Hi Fi Driver.

I do not hear a compromise due to the weight loss ect, It is simply much easier to carry! I am overall very impressed by the results!
 
poobah said:
All other things being equal; a voice coil can develop more force in the presence of a stronger magnetic field.

There are million ways you could comprimise things; probably the best outcome is reduced thermal stress in the voice coil when compared to a non NIB speaker at equal volume.

:)

Does this mean that NIB speakers have thinner gauge voice coil windings to keep the impedance correct?
I suppose if you used the same length of wire in a Neodymium speaker as in a conventional one then ...... hmmm they'd just be very sensitive ...... which they are.

I guess what I'm trying to ask here is: are the voice coils in a Neodymium speaker the same as one with a regular strength magnet?
and
Is a very powerful magnet infinitely more desirable or is best to find a balance of magnet and voice coil?
 
Well I guess that you could reduce the number of turns and use thicker wire... this too would improve efficiency.

There are so many ways to "spread things around", that any quantitative remarks have to invoke the "all other things being equal" clause before any A vs. B comparisons are drawn I guess.

My point being is that one could design a NIB speaker, equivalent in every way with norm and realize no benefit other than perhaps weight reduction. Some of these NIB speakers do indeed have the small diameter voice coils... like the old alnicos had.

I'm guessing that unless the magnetic increases are used to boost effifciency, than there may be no sonic advantage. Consider the reverse; the lack of alnico hasn't hurt things has it?

I have done some PM motor design using NIB... the way we "spread things around" was to achieve higher torque with less diameter (smaller) and higher efficiency because of fewer windings. The point remains... we could have opted to make the motor smaller still and foregone the increases in efficiency.


:)
 
Hi,
neodymium like ferrite is susceptable to magnetic loss at elevated temperatures.
The VC is unlikely to be any different whether neo or ferrite.
The magnetic flux across the gap could be either stronger of weaker and depends on how much magnetic material the designer builds into the circuit.

Since the spec rarely includes magnetic flux you can guess it has not increased, else they would be shouting about it.

The benefit is reduced weight, this being particularly important for portable speakers.
The extra cost comes from the re-engineered magnetic circuit and the extra magnetic material cost.
There are few if any other benefits unless the designer needs to improve the speaker in some particular regard, but that could be achieved with ferrite or alnico if he so desired.
 
Hi,

There is nothing special about NIB magnet speakers particularly.

Huge chunks of Ferrite magnets are still cheaper, if and when they
are not NIB magnets will become the norm for bigger magnets.

Even if NIB remains remains expensive, it offers serious weight reduction.

As it is there is some redesign in the magnetic pole details but
you end up with the same flux density etc in the magnetic gap.

The magnetic design details have more in common with AlNiCo than Ferrite.

:)/sreten.
 
In PA applications neodymium is used to make drivers, that for a given performance will have about half the weight of the ferrite versions. For a double 18" the difference will be around 12 kg (25 lbs) which can make the difference between one man or two man lifts.

Also since the introduction of neodymium the decrease of Qts is encouraged (often in midbass units).

Wkr Johan
 
A decrease of Qts indeed, as can simply be seen on pic's in brochure's. Drivers tend to have lower Qts when haveing a larger magnet.

An other advantage -seen from an "audiophile" point of view- I would recon is less air-flow noises and reflections within the driver.

Where less reflections will probably only be an advantage in mid to highrange applications and less air-flow noises in bass applications (dipoles and ripoles!).

I have two neodyme magnets from a Bowers and Wilkins "Nautilus" , the magnet poles in them are very uniquely shaped (drilled through) obviously to decrease reflections. (sort of reversed horn-shape).
 
Thanks for all the feedback, much appreciated!

I was going to remove the post as a forum search shows the topic has been
well discussed.....guess I should have searched first, so often the case with this forum (well supported, quality posts covering most topics)

Like all things audio, it comes down to application :)

Thanks again!
 
I believe the different size of the NBd magnets allows the manufacturer more versatility in the design.

In that, certain physical variations are available to him that would not be with ferrite.

Seems like I have seen mention of that on one of the Lowther drivers - so I'm not sure that would follow thru with non-full range designs.
 
neo, alnico

yeah, and alnico just sounds good...

unlike ferrite chunks.

neodynium I believe is inherently sheilded, (closed magnetic circuit) like alnico as well, I beleive.

for paper cone stuff, alnico just works. good tone. appplication, as said above...

neodyniumm could be tuned too strong perhaps. creating more bends in the process(?)

I do tend to like the sound of neodynium stuff though. in general.

eh who knows.

Clark
 
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