Neodymium magnets vs Ferrite magnets

[blueae1405]

Well I did notice that alot of very high end speakers use Neo magnets so there's got to be a reason why they use them. Is is just because to make the speakers lighter weight? Is there any performance difference between Neo and Ferrite magnets? Like example Neo would make to voice coil move freely or Neo will make the speakers have less heat etc.

[blueae1405]

I guess what I would like to know is the pros and cons on the Neo magnets and the Ferrite magnets. Or is it overall Neo magnets is the best for speaker drivers?

[human.bin]

i'm not an expert, anyway, differnet materials will take different amounts and then space to generate the SAME force: this will allow for different drivers geometries, and so for different proprietis of the field generated... but you are talking esotheric here, for example take a look at these fancy magnets:

Products
Parts-Express.com:*Tang Band W8-1772 8" Neodymium Full Range Driver | Tang Band W8-1772 8" Full Range Driver full range tb speakers neodymium driver line array point source midrange home theater computer speaker center channel set tube amplifier

also different motor geometries will have different impact on the back-wave radiating behind the driver, expecially on small drivers, it has been said...

different magnets generating different fields will alter the way the cone moves and follows the signal, in this regard Alnico is claimed to be more natural (something like more symmetrical field, i don't know) and it's loved also for instruments like guitars and so.

field-coils seems to be the top, for it can be regulated and usually be stronger than a same-cost magnet can be taken (but it's my guess)

regarding you'r sony speakers the small magnets is certainly ideal to have more volume left inside the enclosure, but then more then the type of enclosure loading they are getting 50hz (witouth giving any db indication) because they are bringing it down to 78db sensitivity, which is adequate for near-field, and let figure out they are equalizing the whole thing... a single alpair-5 has been taken down to 20hz in selaled box this way... and hey, that's a ferrite

[tinitus]

Originally Posted by human.bin

for example take a look at these fancy magnets:

The neo magnets on the TB driver, anyone can buy those at a dollar each
In huge numbers price is hardly worth mentioning

As fore the Feastrex
It really is very special, and expencive, no doubt about it
But maybe most of the money that goes into the magnet design is just a waste
With the same cone design, surround, and careful assembling etc, I wouldnt be surpriced if it sounded just as good with any other good ordinary magnet design
And cost much less
But maybe thats just the point, price

[human.bin]

doesn't the magnet topology on the tangband driver has some benefits on the field behaviour?

[thoriated]

Even the old-school Alnico magnets from WW2 era produced some beautiful sounding speakers that are still sought after today and Alnico has even less "B" than Ferrite.

Actually, the 'old school' alnico magnets have about four times the remanent strength that ferrite does, and their flux is more stable wrt temperature and even in the presence of an opposing flux (up to a point! Beyond that point, they can be 'permanently' demagnetized - until they are remagnetized, that is.). The ferrite drivers that replaced alnico versions were generally heavier due to the greater magnet mass required to give the same gap flux.

Neodymium magnets are even stronger for a given size than alnico and do not as easily 'permanently' demagnetize under extreme conditions, but their Curie temperature (where they lose all magnetism) is very low so they lose magnetic strength faster as they heat up and are also not particularly good at maintaining a constant flux in the presence of an opposing magnetic field.

[mp9]

thoriated, good explanation, how about the lanthanum-colbalt magnet of my fostex 166esr?

[blueae1405]

So does this mean that all magnets have pros and cons? But if that's the case I wonder why for somereason most higher end speakers use Neo magnets. There must be something great about them more than other kinds. But is there not really an answer like yes the Neo magnets are the best or no there are not the best? I just notice you guys don't really give a straight answer on the questions I ask. You say like this magent is good for this but other one is not good for that.

[Iain McNeill]

Yes, as with everything in audio and acoustics, there are pro's and con's. I'll go out on a limb and say that there is never a "best" only a "least bad".

If we're honest, we'll never truly reproduce the same sound field as a quartet playing in your living room. It's all a compromise. That's why there's DIY and why we'll always be here

<edit> and thank you Mark & Thoriated for very educational posts!

[tinitus]

Originally Posted by blueae1405

I wonder why for some reason most higher end speakers use Neo magnets.

A neo magnet assembly look way better than with clumsy ceramic

At other times you see shielded ones
Ofcourse the shielding has a practical purpos
But may also serve another purpos
If nude it might look so small or badly designed you wouldnt even consider to buy it

I would say magnet material isnt really that important
Better to look at pole plate design
And all the other farraday tricks
Impedance curves reveal much of this