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timc
01-15-2010, 11:44 PM
Hi.

I'm involved in a discussion at a Norwegian forum about different magnet technologies.

It is beeing claimed that Neodymium is superior in every way if applied correctly. And that the use of Alnico and ferrite is just a cost saving option.

I have argued that manufacturers like JBL, TAD and Tannoy wouldn't use Alnico without purpose and that with the prices of, say a TAD 4003 a small pluss in manufacturing cost would mean nothing for the sales. The answer was something along the line of: "They don't know better" or "They only measure and don't listen"

Any opinions?

I have read and linked to the ferrite/alnico comment, but I'm wondering if anyone have something more to offer.


-Tim

Ian Mackenzie
01-16-2010, 12:40 AM
http://www.jaycar.com.au/images_uploaded/ferrites.pdf

http://www.school-for-champions.com/science/magnetic_materials.htm


I would not waste time on an opinion stated in a forum.

If you search the topic there are some good posts on types magnetic structures used by JBL

speakerdave
01-17-2010, 12:46 PM
TAD 4003 is neodymium.


Hi.

I'm involved in a discussion at a Norwegian forum about different magnet technologies.

It is beeing claimed that Neodymium is superior in every way if applied correctly. And that the use of Alnico and ferrite is just a cost saving option.

I have argued that manufacturers like JBL, TAD and Tannoy wouldn't use Alnico without purpose and that with the prices of, say a TAD 4003 a small pluss in manufacturing cost would mean nothing for the sales. The answer was something along the line of: "They don't know better" or "They only measure and don't listen"

Any opinions?

I have read and linked to the ferrite/alnico comment, but I'm wondering if anyone have something more to offer.


-Tim

timc
01-17-2010, 02:44 PM
TAD 4003 is neodymium.


It is? My mistake then.


-Tim

speakerdave
01-17-2010, 02:54 PM
I think neodymium is used for different reasons. In the case of the TAD 4003 I'm guessing it is maximum field intensity in the gap for HF extension of a 4" diaphragm with resonances of the 4001 designed out. The 1" 2002, with similar diaphragm design, uses Alnico. Alnico is intense enough for a 1"; the 2002 is very likely smoother than the 2001--I haven't taken the time to compare them, since the 2001 is already very, very good.

I 'm guessing JBL and others who are using neodymium in woofers and other pro gear are doing it so save weight as much as anything else. I don't know what the relative production costs of ferrite and neo are, but ferrite is the heaviest material for a given flux density and the neodymium is the lightest (I think).

Alnico magnet structures for audio are a boutique industry now, lacking the savings of scale, so I would be surprised if it was not the most expensive material just now.

Anybody who wants to argue best magnetic field and leaves out field coil is just passing the time, IMO. I'm guessing it would be the field with the best resistance to short term flux modulation. But then, I'm a bit medieval, majored in liberal arts, and I think you can know stuff by reading and thinking, not like now, with science and everything.