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magnet adhesive fail....

Discussion in 'Amps and Cabs [BG]' started by will33, Aug 25, 2012.

  1. will33


    May 22, 2006
    Some pics trying to show how crooked this thing is...




    This cab has never been dropped, or banged around enough at all for this to have any chance at all of being the result of a physical blow. Ya think voice coil heat could be enough to loosen the adhesive? Make it soft enough for gravity/cone movement while playing to be enough for the magnet to sort of start falling out the back like that?

    Also what type of adhesive is used for these? Is there a better/stronger adhesive that would maybe stand more heat? And what type of solvent would one use to get this thing off? I need to re-seat it on there straight so I can get a recone. Never had this happen before.

    It's a DeltaliteII2512. They get pushed pretty hard when playing outdoors. Not to the point of audible distortion/farting but pretty close. Must be working up there close to xmax limits. Some of these outdoor gigs this summer had an ambient temperature around 100 degrees or close to it, then add VC heat on top of that.


  2. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I think I'd send it back to Eminence and see what they say about it. I would think that they'd be interested in the failure.
  3. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    I'm no expert, but that certainly looks unacceptable.
  4. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    This video showing how to build a speaker might provide some insight. See how they use shims to center things while the glue dries.

    As far as I know, manufacturers use a variety of glues to affix the magnets. The ones that I know of are epoxy and acrylic. So even within those two types, there is variety. Some are thermo setting, some require UV, etc. Different glues require different solvents and they tend to be nasty for these industrial products. I would try some acetone first and see.
  5. will33


    May 22, 2006
    Hey, thanks. Can try acetone. If that doesn't work, maybe just have the reconer deal with it. Was wondering if I could do some of the work myself.

    @ BassmanPaul. I bought these, used, in pretty much brand new condition, a couple years or so ago. From a guitar player, who I guess didn't realize they're not guitar speakers. They'd been loaded in a 412 guitar cab, played for an hour or two, then taken back out, that's it.

    This is the first one of the 4 that's been anything other than good speakers, but, they were not a brand new purchase, so I doubt eminence could do anything about it. They may be interested in the failure, but I certainly don't expect any sort of a replacement or anything.
  6. will33


    May 22, 2006
    Thanks for the video. If I can get the magnet seated straight and tight, I could probably do the recone myself and get it right.
  7. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    +1 talk to Eminence first, even if out of warranty, they have an interest in failure modes to continue development.
  8. will33


    May 22, 2006
    I will email them the pics and description of use, numbers off the driver and stuff then. Wonder if there may've been some fluke on the assembly line that day or if it's just some weird one-time fail. These things are 2-3 years old and have been played a lot. I would think if it was a bad batch of adhesive or something, it would've failed a lot sooner.
  9. js1


    Oct 1, 2006
    Glue can fail over time - it happens...

    I have a first gen Eden 2x10 that I bought used. Over time BOTH speakers had their magnets shift. To recone, I needed to go to a place that had a demagnetizer/magnetizer. They demagnetize, pull the magnet assembly apart, reglue, remagnetize, then recone.

  10. 1958Bassman


    Oct 20, 2007
    By the time the distortion is audible, it's in whole numbers of percentage, sometimes double-digits.
  11. will33


    May 22, 2006
    True. Figuring xmax is 10%, may've been exceeding it on a couple of leading edge note attacks once in a great while, but I'm pretty good at stopping short of abusing stuff. Going to do a 3rd 112 for outdoor gigs though, just so I don't push these quite so hard. Never slapped a coil into the back, no creased cones or anything, just the magnet thing.
  12. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    If the driver magnet got hot enough to melt the adhesive I would have thought that the magnet itself would be toast. Neos don't take heat well that's why the heatsinks on the driver.

    Let us know what Eminence says - I'm curious. :)
  13. Hi.

    Excuse my ignorance on anything NEO, but isn't that just the magnetic interference shield?

    On the very few cheapo NEO's I have dismantled, the magnet has sat on the top or on the bottom of the pole. Not assuming that all the NEO's are constructed the same way just because virtually all the ceramics are of course, but it wouldn't make much sense to move the motor that far back of the support structures. Not to an engineer like me anyway.

    Unless we are looking at a co-axial drivers Hi-Freq drivers motor that is. In that case the crooked part still looks like a MI-shield to me though. And those are often glued so badly that if You look at 'em in a bad way, they'll fall off ;).

  14. Sub'd. Please do report back.
  15. I'm not well versed in speaker tech, but I believe ambient temperature could weaken the adhesive in addition to voice coil heat. Does the coil look black or burnt in any way?

    This page may help with figuring out what happened. The site is mainly hi-fi related but some of the info is still applicable to bass reproduction. It's got a fair amount of info on speaker failure.

    Hope this helps.
  16. will33


    May 22, 2006
    Wow. All I can say is Eminence kicks butt, man.

    Was over at the shop where my gear is last night. Took a couple more pics of my driver and sent them in an email I wrote up to Eminence inquiring about this failure. I included every detail I could think of as far as how these things are used, under what conditions, temperatures, etc. Probably to the point of going overboard with minute details but I just wanted them to have any info that might be helpful. I asked them what they think may've caused this and what type of adhesive to use, etc. 'cause I needed to get this magnet straightened out so I can get my driver reconed.

    I was expecting maybe a couple of repair tips, or maybe an address of a repair shop that is one of their dealers or something, but hell, by 8:30 this morning I had emails back saying it looks like the adhesive failed and that they would like to investigate this further. They gave me an RA number and said to send them my driver so they could look into it and they'd send me a replacement one. Even though I told them these things are probably 3 years old and I didn't even buy them brand new in the first place. That's awesome.:hyper:

    I haven't messed with this thing yet. It's sitting just like it was when I took it out of the cab so they shoukd have a good specimen there. So, boxing it up to send to Kentucky and getting a new driver. Yay.

    @ T-bird.---these aren't shielded like hifi drivers, that is the magnet. Here is a pic of it sitting next to a good one so you can see how far it has backed out of there.

  17. Myth_103

    Myth_103 Supporting Member

    Excellent! I'm glad to know Eminence is standing by their product. I've never experienced anything from them less than positive. And lucky you for the new speaker!
  18. will33


    May 22, 2006
    Ya, totally above and beyond as far as I'm concerned. They want to run this thing through the lab and find out what happened.

    These things go for $150 at parts express right now. Whhen I boight them from that guitar player I gave $240 for 4 of them, so $60 each. At that time, just a couple months after Neo went through the roof, they listed for $229 each.:eek:
  19. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I told ya they'd be interested! :D

    I'm very happy for you Will.
  20. will33


    May 22, 2006
    Yeah, that was some pretty darn good advice Mr. BassmanPaul...thanks.

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