Magnetic Shielding

Discussion in 'Speakers' started by ChipD, Jan 6, 2004.

  1. ChipD

    ChipD Extra

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    Is it normal for main front speakers to not be magnetically shielded? I am about to buy the B&W DM603 S3 speakers and I realized they are not shielded. In addition, I was told that B&W will NOT add shielding for an extra cost. This is a problem for me because we really don't have room to move the speakers away from the TV. Also, even if we did have room, I'm can't predict our setup in the future. Any suggestions? Are most brands like this? Do I have to abandon my B&W selection and look for different speakers?

    Thanks.

    Chip
     
  2. WayneO

    WayneO Supporting Actor

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    I'd say most aren't, and some manufacturer's offer an option at additional cost. Hard to say whether the speaker will affect your TV until you get em in the house to where they'll be. Whether or not you want to bring the B&W's home to try is up to you. As a Paradigm owner, I know shielding is an option for many of their speakers so you might give them a listen if you abandon the B&W idea.
     
  3. Ernest Yee

    Ernest Yee Supporting Actor

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    How far away can get the speakers away from the television? If you at at least a foot on either side, it shouldn't be a problem.
     
  4. Chu Gai

    Chu Gai Lead Actor

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    So long as your speakers are about 2 feet away from the TV, you're fine. At approximately 2 feet, the magnetic field in the drivers has a field strength approximately equal to the earth's magnetic field. You'll often see computer speakers shielded as well as center channels because of their proximity. Even then, it's not unusual for there to be a slight interaction but that's usually solved by increasing the distance slightly.
     
  5. Sheldon-m

    Sheldon-m Stunt Coordinator

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    The only TV I think you need sheilding for are tubed tele.
    they are the only ones I have seen that are affected by speakers that are not sheilded. (i could be wrong) That is really something all speaker should have. I bought the Fluance AV-F5 and they came sheilded. They are a tenth of what B&W are worth.
    I love them[​IMG] .
     
  6. WayneO

    WayneO Supporting Actor

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    It can happen with a RPTV, my sub can blur it if it's too close.
     
  7. Greg_TSL

    Greg_TSL Stunt Coordinator

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    If you have the space and really like B&W you could go with center channel speakers all across the front, they are shielded. I use LCR 600s and they sound lovely.
     
  8. ChipD

    ChipD Extra

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    I have a few questions about the tv interference...

    1. Do the speakers have to be hooked up for them to cause a problem with the TV? I did set a single DM603 s3 next to my tv and didn't notice any problems (it wasn't hooked up).

    2. Will the entire screen turn green? What exactly happens?

    3. How long does it take for the tv to start having problems? immediately? an hour?

    4. Would it make a difference/cause more interference if I had BOTH speakers next to the tv (instead of just one)?

    5. Could unshielded speakers cause problems with my dvd player, receiver, or vcr?

    6. Also, if there doesn't appear to be any interference, how can this be explained?

    Thanks!
     
  9. Dan Halchak

    Dan Halchak Stunt Coordinator

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    1. No speakers do not have to be hooked up to cause interference, it's the magnets that cause the intereference.

    2. The picture will go darker on the side where the speaker is. The colors of the picture will start to distort as the speaker (magnet) get's closer to the picture tube.

    3. You will notice it immediately. If you have a small speaker you can move it closer/father and watch the picture change. (However I do not recommending you doing that, you can eventually harm the CRT).

    4. Yes, two magnets are going to cause more intereference than a single one. All you can do is try putting the speakers roughly where you would have them and see. If the speakers are roughly 1' away from the TV, you shouldn't have any problems. The bigger the drivers, the bigger the magnets in the speakers and the further away you have to place them.

    5. DVD, Receiver, no, there's nothing really Magnetic in them to cause them to have problems. VCRs, yes, they are all about magnetics.

    6. Some TVS are more sensitive to stray magnetic fields than others, so this could be why you might not be experiencing anything... Best thing to do is put on something that's really bright picture wise (has a lot of white). Then have someone walk the speaker closer to the TV while you watch, you can then tell how far the speaker needs to be. I found my DM603s and 604s need about 1' of space, after that there's not real interference.
     
  10. WayneO

    WayneO Supporting Actor

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    1. No
    2. Colors near where the speaker are get blurred, turn different colors than natural.
    3. Sometimes right away, sometimes a minute, if it's on the very edge of where it'll affect the tv.
    4. Shouldn't if they're equal distance on each side.
    5. No
     
  11. ChipD

    ChipD Extra

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    If I store VHS tapes next to my unshielded speakers, could this potentially damage the tapes (stored a few inches away in my entertainment center cabinet)?
     
  12. WayneO

    WayneO Supporting Actor

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    I have my tapes about a foot away in a drawer next to my speakers for years and haven't noticed any problem.
     
  13. STLMIKE

    STLMIKE Stunt Coordinator

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    I'm glad to know that this is an issue. I'm on my second set of Infinitys (both are shielded), and I always assumed that speakers were shielded.
     

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