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Thread: Neodymium or ceramic?

  1. #1
    RIP 2010 scott fitlin's Avatar
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    Neodymium or ceramic?

    I have been reserching 15in woofers, everyone makes them now with neodymium magnets! JBL, as well as others! There are a few different models, including JBL, that interest me.

    My question for today is neo,s reliability! A few guys I have spoken to, sound contractors, have told me to stay away from neodymium magnet woofers because the magnets have a habit of becoming completely discharged if overheated! I knew this was in fact a problem with neo several years ago, and neo was only really used for compression drivers etc! But now every manufacturer has seemingly high performance, and lightweight woofer models available featuring neo magnets, so whats the real deal? Is neo a reliable magnet in a high power woofer, in commercial use?

    An enquiring mind needs to know!
    scottyj

  2. #2
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    Good-bye Mr. Anderson.

    My...name...is...Neo!


    Many of the issues have been addressed, but a neo magnet still has its inherent virtures and vices.

    Here's what one manufacturer has to say about it and why his design modifications make it a great magnet.

    http://www.euphonicaudio.com/2005/te...eo_magnets.htm

    You can also check out the Gaussboys general warning about neos, including what heat and fracturing can do.

    http://www.gaussboys.com/warnings.php

    I always find musicians' discussion on these kinds of topics enlightening, if anecdotal, so you might enjoy this:

    http://www.musicplayer.com/cgi-bin/u...5;t=011558;p=1

    A brilliantly executed neo magnet is a remarkable thing, i,e,, heat sinks, liquid cooling, thermal dissipation casings, etc.
    Out.

  3. #3
    Administrator Mr. Widget's Avatar
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    I am not sure if this is relevant, but I had a mishap with an imported compression driver with a neodymium magnet and it could not be repaired since no one here had a magnetizer powerful enough to recharge the magnet once the repair was complete. I believe one of our European members had a similar problem with a JBL neodymium compression driver and was told that it must go back to the factory for repairs.

    I would assume the woofers would have the same issues.

    Widget

  4. #4
    RIP 2010 scott fitlin's Avatar
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    Very interesting!

    Thank you, Dome, good reading! I am aware there will be sonic differences between ceramics and neo,s, and its interesting to note that some find the mids of neos somewhat brittle sounding! I have no idea, I havent, as of yet, auditioned any myself! I was surprised that two different sound guys told me to stay away from neo,s! I know about the Aurasound 18 back in the 90,s, demagnetizing from extreme use, especially if they were blown, but would have thought since most manufacturers offer this as a regular product in their respective lineups these days, the heat issues have been solved!

    Keep it comin, seems from the little bit Im reading, heat IS still an issue!
    scottyj

  5. #5
    RIP 2010 scott fitlin's Avatar
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    !

    Quote Originally Posted by Mr. Widget
    I am not sure if this is relevant, but I had a mishap with an imported compression driver with a neodymium magnet and it could not be repaired since no one here had a magnetizer powerful enough to recharge the magnet once the repair was complete. I believe one of our European members had a similar problem with a JBL neodymium compression driver and was told that it must go back to the factory for repairs.

    I would assume the woofers would have the same issues.

    Widget
    Well, then serviceability becomes an issue should the magnet be discharged! And, yes it is relevant, as it has to do with reliability!

    Thank you!
    scottyj

  6. #6
    pelly3s
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    I use Neo drivers in a lot of my boxes at work, all my monitors have 2255's and my double 18s are 2258's. I also use some EV Ndym 6 horns and I havent had any issues. As was mentioned though the magnetizer that we have wont even touch them. Im telling you I would rather take the chances then break my back moving the double 18s. Just my personal opinion. I know there are a lot of people out there who dont like them but i havent had any issues yet

  7. #7
    RIP 2010 scott fitlin's Avatar
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    Well...

    As I said, the neo woofers i am looking at are very interesting! Thus far, two sound contractors have told me to stay away from them! Thats why I am asking questions. OTOH, since Dome turned me on to talkbass.com, I have found some more interesting reading from the musicians! I feel bass guitarists put their woofers through more abusive use, than playback audio apps! So if they can withstand the rigors of live, uncompressed, sometimes highly distorted bass, they can withstand pre recorded music!

    As to their sound? Well Im just gonna have to order two drivers and see for myself what they do or dont do!

    But heres another interesting read > http://www.talkbass.com/forum/showthread.php?t=167954

    The one thing I seem to have come across is they, ( neos ), do have a midrange bump! Some like, some dont, and this may account for the brittle sound some claim they have!

    scottyj

  8. #8
    Tom Loizeaux
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    JBL uses Neo magnets not only on their high end audiophile speakers (K2 Series) but also in their HLA and VerTec line array systems. Both the HLA and VerTecs are considered "high end" in sound reinforcement circles. They do sound very good, are relatively light, buy they are expensive! These systems are moved around for each job, so weight is a major concern. Though time will tell, I believe Neo magnets are going to be the material used in the coming years.

    Tom

  9. #9
    RIP 2010 scott fitlin's Avatar
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    I agree

    Quote Originally Posted by Tom Loizeaux
    JBL uses Neo magnets not only on their high end audiophile speakers (K2 Series) but also in their HLA and VerTec line array systems. Both the HLA and VerTecs are considered "high end" in sound reinforcement circles. They do sound very good, are relatively light, buy they are expensive! These systems are moved around for each job, so weight is a major concern. Though time will tell, I believe Neo magnets are going to be the material used in the coming years.

    Tom
    Neodymium is the magnet material of the future! Weight being the primary reason! The woofers Im looking at being good for horn loading, are only 10lbs each! Installation would be a walk in the park!
    scottyj

  10. #10
    RIP 2010 scott fitlin's Avatar
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    Pelly

    Quote Originally Posted by pelly3s
    I use Neo drivers in a lot of my boxes at work, all my monitors have 2255's and my double 18s are 2258's. I also use some EV Ndym 6 horns and I havent had any issues. As was mentioned though the magnetizer that we have wont even touch them. Im telling you I would rather take the chances then break my back moving the double 18s. Just my personal opinion. I know there are a lot of people out there who dont like them but i havent had any issues yet
    Besides the lighter weight, whats your opinion of neo magnet woofers sound compared to the more traditional ceramics? Or at least can you compare the sound of the neos your currently using, to the drivers they replaced?
    scottyj

  11. #11
    Dang. Amateur speakerdave's Avatar
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    Member Geiger points out on another thread that the number one concern in engineering a new product is to minimize warrantee returns. Unless we think JBL technical staff is walking off a cliff like grunion, it's a safe chance that neodymium magnets will continue to function under normal use within application.

    I'm puzzled by this idea that the frame can be made light because the magnet weighs less. I always thought it was the force exerted by the motor on the cone (and air) that required the rigidity of the cast frame. It seem to me that with a less massy motor a MORE rigid frame would be necessary. Any physicists around?

    David

  12. #12
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by speakerdave
    I'm puzzled by this idea that the frame can be made light because the magnet weighs less... Any phycisists around?
    I guess it is physics in the Newtonian sense.

    The greatest physical stresses on the drivers come from transportation. Think about a 10-15 lbs magnet structure cantalevered off of the back of a driver frame.... a few good bounces will show you what angular momentum is all about.

    Widget

  13. #13
    pelly3s
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    scott they sound better than any of the other JBLs i've used. I would use EVX 180s but i couldnt move them but thats because i love the sound of the 180s. The subs I use are internally the same size as a 4880 and the 2258s have really been the only ones in those boxes. they are a very accurate speaker and they are very efficient for what they are

  14. #14
    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by Mr. Widget
    The greatest physical stresses on the drivers come from transportation. Think about a 10-15 lbs magnet structure cantalevered off of the back of a driver frame.... a few good bounces will show you what angular momentum is all about.
    Oh, right! UPS and roadies!

    Thanks,

    David

  15. #15
    RIP 2010 scott fitlin's Avatar
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    You know whats funny?

    Quote Originally Posted by Tom Loizeaux
    JBL uses Neo magnets not only on their high end audiophile speakers (K2 Series) but also in their HLA and VerTec line array systems. Both the HLA and VerTecs are considered "high end" in sound reinforcement circles. They do sound very good, are relatively light, buy they are expensive! These systems are moved around for each job, so weight is a major concern. Though time will tell, I believe Neo magnets are going to be the material used in the coming years.

    Tom
    The JBL neos are VERY expensive! But the European speaker companies neos are less expensive than their ceramics, and even less expensive than JBL ceramics!

    Theres another Italian manufacturer named Ciare, some of the Pros are liking this brand alot, and they are really inexpensive, neo and all! B & C,s neos are cheaper than their ceramics, go figure!

    Is raw neodymium cheaper on the other continent?
    scottyj

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