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Magnetic Shielding of speakers

Discussion in 'Speakers' started by Freelancer, Oct 27, 2005.

  1. Freelancer

    Freelancer Member

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    Hopefully this is not a dumb question, but how do i magnetically shield my centre/front left and front right speakers from my LCD TV screen? I might get some full size speakers and nowhere can i see whether they are already shielded on their spec, so i wondered how one would do this?

    Thankyou. :lease:
  2. Will Scarlet

    Will Scarlet Member

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    Hi,

    I think I'm right in saying that most centre speakers tend to be shielded because of the need for them to be near the screen. Regards front left and right speakers I'm not sure. My fronts are not shielded, and are around 18" either side of my 32" crt with no ill effects. Of course maybe LCDs suffer more than crts, if so ignore me and I'm sorry as this post is of little help to you.
  3. pragmatic

    pragmatic Active Member

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    LCD is uneffected by the magnetic forces of a speaker, CRT's are becuse the elctrons get sucked in the direction of the magnetic field, moving them from the place its ment to hit on the screen.

    An LCD works on an entiely different principle for producing an image, so no need to worry.

    Pretty much all home cinema speakers are shielded, and even most hi fi ones are these days, but it should be mentioned in the documentation, or even sent and email of to a manufacturer if you need to be absolutly sure.
  4. Knyght_byte

    Knyght_byte Active Member

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    i like watching a TV with unshielded speakers near it.....lots of purples and greens...lol

    LCD isnt affected in the same way, HOWEVER, its never wise to have very large speakers near anything that works like a computer as the electro magnetics can still cause problems (they can wipe bios or firmware info on memory chips in computers or electronic equipment........granted they do need to be somewhat powerful to do this, but i wouldnt chance it...heh)
  5. Freelancer

    Freelancer Member

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    Thanks for the advice guys.

    However one thing i'm still curious about. If i happen to get speakers that for some reason aren't shielded, what can i do to protect my LCD screen (just to be sure), ie, HOW do i shield the speakers? Is there some sort of material you buy, or do you just have to place the speakers at a safe enough distance away from the screen - if so how is this distance calculated?

    Oh and stupid question, but the speaker cover mesh that you can take off from some speakers - they aren't shields are they? They're just dust protectors right?

    Thanks.
  6. conkerman

    conkerman Member

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    You don't need to for an LCD TV. It makes no difference.

    Covers are cosmetic and to stop little fingers interfering with drive units.

    There is no way that the magnet in speakers can interfere with an LCD screen under normal circumstances.

    Just relax and go for it :)
  7. Cable Monkey

    Cable Monkey Active Member

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    Shielding is appropriate to CRT televisions only. Shielding refers to stopping the magnets that are part of all speakers from interfering with the flow of electrons in the tv tube which can be deflected causing distortion and mis-coloring and can lead to permanent damage. LCD's and plasmas are not affected by magnets and so do not need speakers to be shielded.
  8. pragmatic

    pragmatic Active Member

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    To wipe the chips ect... You'd have to have a very power magnet pretty much on the chip itself, magnetic forces get week very quikcly because of the inverse square law, so as long as you don't put the spaker inside the screen you'll be ok (even then it probably wouldn't do anything). If you wanted to shield your speakers you need to use a magneticaly absorbant metal, usualy aluminium or steel are used but as said earlier there isn't a need.
  9. Knyght_byte

    Knyght_byte Active Member

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    and why do you think they say never put an unshielded subwoofer near a computer? for the reason that it has a massive electro magnet in it and can create enough of a field to interfere.....its unlikely it would, but its possible if it was close enough.....mostly the company is just making sure there is no come back if someone did decide to stick their HDD unit on top of their sub cuz it was handy, or possibly their LCD screen....heh....

    but putting a pair of conventional sized speakers near an LCD wouldnt be a problem....
  10. pragmatic

    pragmatic Active Member

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    Remember that most amps have a huge internal power tranformer and some use torriodal one, these by ther very nature produce large magnetic interference (stick a computer psu side to close to a crt monitor the picture will jump) but the av IC's are not damaged by this evn though there is very close proximity, yes they may be sheilded ect but overall it a case that it could happen so we are warning you more than anything else.

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