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Bucking Magnets, Where???

Discussion in 'Home Cinema Building DIY' started by Paul Smith, Aug 5, 2004.

  1. Paul Smith

    Paul Smith
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    Hi,
    Does anyone know where you can buy bucking Magnets for shielding drivers in the UK???
    Cheers,

    Paul.
     
  2. ShinObiWAN

    ShinObiWAN
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    CPC, farnell or Maplins would be you best bet.
     
  3. Paul Smith

    Paul Smith
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    Unfortunately they don't supply them!
    Would you believe it CPC supply shielding cups, but not the bucking magnets to go with them!
    Any other ideas?

    Paul.
     
  4. banners

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    Hi Paul, what application's the bucking magnet for? The close proximity of the additional magnet may change the specs of the speaker.
    I made some speakers some time ago to be placed either side of the TV and soon had a problem with screen distortion. I played about with magnets etc but found a nice piece of 2mm sheet steel placed in the cab near the speaker magnet worked quite well.
    Dunno if you've seen this page :- http://www.lessemf.com/faq-shie.html
    Some info half way down the page

    HTH
    Steve
     
  5. Paul Smith

    Paul Smith
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    Hi,
    Thanks for the reply,
    Yes I've seen that page before.
    I build my own speakers and I like them to be properly shielded and the best shielding comes from using a bucking magnet, (pieces of sheet metal never provide as good results).
    As for changing the T/S parameters, according to many sources this is only Very slight and will not be enough to need to alter box design (and is certainly not a problem for home built speakers).

    The problem is that at the moment the only place I know you can buy bucking magnets from is partsexpress in the US (and postage would be just too expensive).

    Paul.
     
  6. Paul Smith

    Paul Smith
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    So, it seems no-one (at least no-one reading this thread) knows of a place in the UK to buy bucking magnets, I feel that's a shame!
    If you do know where to go please post.

    Paul.
     
  7. banners

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    Paul, have you considered contacting the manufacturer of your drivers? I'm not sure but maybe they could supply you just the magnet (same as current units) and then you use them? Could you have not just used shielded drivers in the first instance?
    Steve
     
  8. Paul Smith

    Paul Smith
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    Hi,
    Thanks for the reply,
    I do currently use shielded drivers, mainly because I like to choose where my speakers are positioned with no restrictions due to magnetic fields.

    However unfortunately for the DIY'er shielded sub drivers don't seem to be readily available.

    You might be onto something with "contacting the manufacturer" for the same magnets and it would certainly be worth a try.
    But I suspect a lot of drive units are shipped complete from outside the UK and buying just a magnet may end up being just as expesive as ordering from partsexpress US anyway (although I may be wrong).

    I just thought it would be nice to be able to buy any drive unit I fancied and have the possibilty of being able to shield it without having to radically increase it's price by ordering extra bits from abroad.


    Paul.


    p.s. At the moment if I want a small bucking magnet I pop round the local scrapyard and get them off old car speakers (however they are normally quite small and you can't always get the exact size needed).
     
  9. banners

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    I think what I'd try to do in your situation is keep an eye out for another sub/woofer on ebay(cheapy cheap!) or visit your local car accessory 'boom boom' shop for cheap drivers. Try to find something with similar magnet dims and rip that off and glue to your current driver magnet(clamp to try first tho'! :eek: )
    Alternatively, could you try Isobarik loading with another identical driver? If you can mount them back to back I think you would acheive the same results with the added bonus of halving the box size.
    Steve
     
  10. Paul Smith

    Paul Smith
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    But I'd still prefer to just buy the right sized magnet on it's own though. :)

    Paul.

    p.s. I also forgot to mention that the bucking magnet "is usually smaller in diameter and height than the primary magnet", so ripping apart another Adire Shiva or Tempest probably wouldn't help.
     

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