Confusion about sub magnet

Discussion in 'Speakers' started by Rick Westfall, Dec 8, 2003.

  1. Rick Westfall

    Rick Westfall Stunt Coordinator

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    What the heck is Neodymium and how does it help if the sub magnet is made of it? Best I can tell is that it's lighter...maybe. How is it better than say...ferrite?
     
  2. PaulT

    PaulT Supporting Actor

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    Neodymium magnets are currently the strongest permanent magnets known. They also have very high strength to weight ratio, so Manufacturers can build smaller speakers with the same magnetic strength as ferrite or other magnets if they use neodymium.

    Do a web search for Neodymium, Rare Earth Magnets, or Neodymium-Iron-Boron magnets.
     
  3. Jason Padrick

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    How about AlNiCo magnets? Those are supposed to be pretty good too right?

    Don't see anyone making subwoofers with Neodymium or AlNiCo. This because of cost considerations?

    *Insert newb alert*
     
  4. Michael R Price

    Michael R Price Screenwriter

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    No particular materials are better than any others, as far as I know, it's specific to the design. Neodymium magnets are lighter, though.
     
  5. Rick Westfall

    Rick Westfall Stunt Coordinator

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  6. Jason Padrick

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    Hmm, interesting. Their subs only have 9 oz. of magnet, where other sub drivers have hundreds of ounces for ferrite. Just checked out their site. Don't look too shabby.
     
  7. ThomasW

    ThomasW Cinematographer

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    There are several companies making woofers with neodymium magnets.

    Focal, AuraSound, MCM, etc.....
     
  8. Chuck Schilling

    Chuck Schilling Stunt Coordinator

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    It's ALL in the application. There is a school of thought (I happen to belong to it) that believes that AlNiCo magnets provide warmth and contribute to mellowing the tone of the output. AlNiCo, like neodymium, is much lighter than ceramic (ferrite) magnets of the same magnetic strength, but is much more expensive and, theoretically, loses its magnetivity more quickly. However, this is over a period of decades - fifty years or more I'm told before there is an audible change in sonic characteristic because of the demagnetism. The problem with AlNiCo is price - it's very expensive to manufacture (probably because of the cobalt, but also because of the lack of demand due to the popularity of cermic magnets).

    For a subwoofer, neodymium is probably the ticket given its light weight and strong magnetism. You don't want "warmth" in a subwoofer - you want clarity, rapid attack and punch, and those are not the qualities that an AlNiCo magnet will improve in a driver. A ceramic magnet can do it, but the weight penalty can be prohibitive. As an SB-2+ owner, I can attest to this - that sucker is heavy! As are other high-power handling ceramic loudspeakers - for instance, the Electrovoice EVM-12L drivers in my guitar amp pull the weight of the beast to over 120 lb!

    Neodymium allows the driver manufacturer to build very high power rated drivers with a relative minimum of weight. A metallurgist could probably also provide us with some interesting properties of this alloy which might make it *very* useful for certain loudspeaker designs.
     

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