Is it safe to leave Neodymium-loaded cabs in the trailer?

Discussion in 'Amps [BG]' started by Rockin Mike, Feb 12, 2013.


  1. Rockin Mike

    Rockin Mike Supporting Member

    Joined:
    May 27, 2011
    I understand the issues with leaving regular speaker cabs in the trailer between gigs.

    Are neos any different? Will the magnets be affected by temperatures in the trailer (Florida gets pretty hot in the summer) or humidity?
  2. Arjank

    Arjank

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    Oct 9, 2007
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    Above Amsterdam
    Though lower then regular ferrite magnets, the curie temperature of Neodymium is between 310-400 °C.
    Don't know how "hot" it gets in that trailer, but you'll have to make it real steamy to reach those temperatures :smug:
  3. Rockin Mike

    Rockin Mike Supporting Member

    Joined:
    May 27, 2011
    from Wikipedia:
    "As the temperature is increased towards the Curie point, the alignment (magnetization) within each domain decreases. Above the Curie temperature, the material is paramagnetic so that magnetic moments are in a completely disordered state."

    Which leads me to believe that magnets start to lose their magnetism as temperatures go up and when the Curie point is reached, they are completely gone.
  4. Arjank

    Arjank

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    Oct 9, 2007
    Location:
    Above Amsterdam
    Yes, they will.

    But remember that the voicecoil also can get freakin' hot and thus increasing the temperature of the magnet. You will not reach those temps in a trailer on a sunny day in Florida.
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  6. Bredian

    Bredian

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    Apr 22, 2011
    As long as the trailer is heavy enough, your gear won't float away.
  7. Arjank

    Arjank

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    As stated, the "magnets" will disappear once the curie temp. is reached :smug: A long trailer will not prevent this..... :p
  8. Rockin Mike

    Rockin Mike Supporting Member

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    May 27, 2011
    Actually it's the mass per unit volume that matters for floating. A battleship is plenty heavy, but they mostly float unless they're leaky.
  9. majortoby

    majortoby

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    Location:
    Tampa, Fl USA
    Your magnets probably hit 200+ degrees after a few minutes of playing. Even down here in sunny Florida, I doubt we have anything to worry about. Rock on completely with lighter components :) :bassist:
  10. jaywa

    jaywa

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    Location:
    Iowa City, IA
    I know back in the day of the aluminum cone Hartke cabs, us northerners were always well advised to let those things warm up to room temp before pumping sound thru em. Many shredded drivers from being turned up too loud, too soon after a week of subfreezing temps in the trailer.

    Probably not at all relevant since we're talking neo drivers and heat, but just sayin.
  11. Arjank

    Arjank

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    Above Amsterdam
    Were the cones shredded or the voice coils?
    Aluminium can get brittle with sudden/extreme heat changes and if the voice-coil-former is made of aluminium this might happen, but I doubt it.
  12. micguy

    micguy

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    May 17, 2011
    I'm a Physicist, and design audio gear for a living. I seriously doubt that you'd hurt an aluminum cone speaker from temperature changes. About the only thing I could see is, if the voice coil gets frozen (water ice) in the gap, and you hit it hard before it thaws, maybe you could bend the voice coil. Of course, if that's even a concern, it'd be one for any speaker, not just aluminum.

    Neodymium magnets were developed for automotive starter motors. They're OK in the cold or heat of the outdoors.
  13. jaywa

    jaywa

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    Location:
    Iowa City, IA
    The cones.
  14. Arjank

    Arjank

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    Location:
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    Think so too.
    You think it's the same with Kapton? It will change in form more then aluminium(thus easier to "scratch" the voice-coil wire to the side of the magnet gap) but it will allways get back to it's original state.
  15. Arjank

    Arjank

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    Oct 9, 2007
    Location:
    Above Amsterdam
    Wow.
    Never heard of that before.

    I only heard some people break ceramic cones from Thiel&Partner... due to excessive excursion.
  16. john m

    john m Supporting Member

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    Jan 15, 2006
    Speakers come unglued in extreme temps.

    Cone material ages faster too.
  17. 4-stringB

    4-stringB

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    Tallahassee
    What probably did that was condensation. Think about it, a week or two at sub-freezing, then brought into a warm, humid room. They would be instantly be covered with a layer of moisture. This would short out any electronic device, as well as weaken the paper cone/adhesives of the drivers...'jus sayin...I've even known power drills and such to act pretty funny when first brought in from the cold....
  18. T-Bird

    T-Bird

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    Apr 29, 2007
    Location:
    Finland (Northern Europe)
    Hi.

    I know that this ain't what You're asking about, but leaving neo cabs in the trailer just makes it easier for the lowlifes to steal 'em.
    Put a band sticker on it, and Your worries are over.

    As for the technical side of it, zero issues.
    Unless the manufacturer used some very shoddy material.

    The VC adhesive, the spider adhesive, or the surround adhesive will deteriorate much sooner than the neodymium starts to lose its properties.

    Regards
    Sam
  19. Rockin Mike

    Rockin Mike Supporting Member

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    May 27, 2011
    I think humidity might affect the rigidity of paper cones.
    Also what was said above about glue coming unstuck and theft are real concerns.

    I guess one of the advantages of neo is it's so light I CAN bring it in the house every night.
  20. warnergt

    warnergt

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    Location:
    Vortex of sin and degradation
    The magnetism returns once the temperature drops back below
    the Curie point. It isn't lost forever.

    Many soldering irons use this phenomenon to regulate temperature.
    A magnet closes a switch which heats up the iron. Once a
    certain temperature is reached, the soldering iron tip loses
    its magnetism and the switch opens. The heating stops,
    the tip cools back down below the Curie point where the
    magnetism returns and closes the switch again to start heating
    once again. It's a magnetic thermostat.
  21. john m

    john m Supporting Member

    Joined:
    Jan 15, 2006
    I always wondered why there was a magnet in the tip or my 100 watt Weller.

    Thank You





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