Video shielding classic Monitor series

[heiney9]

It seems like I remember seeing this discussed before but my search comes up with nada. It seems we came up with lead sheets with some kind of stick 'em on the back to line the interior of older Polks to make then sheilded so as not to cause a CRT tube to discolor. Is this possible? Anyone remember the discussion? I think Ken S. was involved somehow.

If not, is there such a product as lead lining that could be put inside the cabinet to sheild the magnetic field enough to use as center channel for an HT rig?

I have an interested party in my single 5b, and he wants to use it as a center to go along with his 10b's. Is there anyway to sheild the drivers if it's going to be close to a CRT?

H9

[nadams]

they're called bucking magnets. Basically the opposite polarity of the original magnet, it sticks itself to the driver and cancels out the magnetic field. You'll need one for the midrange and one for the tweeter.

[heiney9]

Thanks, Nadams! Do you know if they are expensive and can you get them at Home Depot or Lowes or Rat Shack? I'll pass the info along to my prospective buyer.

H9

[nadams]

While I had the right product, it seems I didn't have my facts straight. Do a search for "bucking magnets" on google and you'll find a wealth of information to pass on to the buyer. One thing to be aware of is that when using them, you're altering the magnetic field, which means the operating parameters of the driver will change.

[I-SIG]

I added bucking magnets to the SDA-1c Studio's I had. Ken didn't seem to think it was a big deal adding them. They were like 8 bucks for the mids and 6 for the tweets. Polk shipped them straight to me. At Ken's suggestion I epoxied them to the drivers.

They made a huge difference as I had to get the TV within a couple of inches for any interference.

Wes

[Sumbrada77]

Hey Heiney9 this is Sumbrada77 the interested party of your 5b. Reading this
set i di a little checking on sheilding. Maybe these to links can help others as it did me. More time to play.
http://www.hometheaterforum.com/htf/archive/index.php/t-18575.html
http://forums.audioholics.com/forums/showthread.php?t=21091
http://www.andrewrondeau.com/Voight%20Pipes/shielding.html

[heiney9]

So did you get your questions answered? Thanks for the links. Is the single 5b going to work out for you?

H9

[Polk65]

It depends on the height of the speakers and the CRT TV. Sometimes you can succeed by just raising the TV a few inches. I slapped some bucking magnets last year on the mid-woofers closest to my TV and can move the speakers within 12" of the TV with no visible effect.

Last week I tried the air duct cap mentioned in link #3 above. I tried it alone and with magnets but it had no effect. If I find some cheap mu-metal somewhere I may give that a try but for now I am done with this.