Help with bucking magnets

[captain]

I am currently in the process of converting a KLF-20 into a center channel. I need to shield the speaker. Klipsch no longer carries bucking magnets. I check with Parts Express and they no longer carry a magnet large enough to shield a 10 woofer. Any suggestions?

[Frzninvt]

MCM Electronics or Mouser perhaps.

If not do a Yahoo or Google search it may lead you to a place that specializes in them.

[captain]

Thank for the info, tried both suggestions no luck. Tried google once, maybe I will surf some more. Thanks

[Frzninvt]

Try madisound.com, it came up in a Yahoo search of bucking magnets.

[captain]

Thanks again, still no luck. Madison Elect. Carries smaller bucking magnets, nothing larger enough for a 10 woofer.

[michael hurd]

Did Klipsch specify what size of magnet ( ounces ) that they did use? If all else fails, you could always cannibalize a cheap pair of 8" or so speakers, taking the magnet apart with a hammer and chisel. Then glue these on the back of the woofers, the correct way, and you should be fine.

[colterphoto1]

how does that work Michael? does the magnet only have to be close in size/gauss and fitted back to back? Or is it an exact science? Do all drivers need to be 'shielded' in this manner or just the big woofers?

Michael

[michael hurd]

I am not at all a speaker designer, so I cannot say whether it is an exact science or not. However, if klipsch specified a certain size magnet, I would try to find one that is close to the same size.

The woofers obviously have the largest magnet, and therefore the largest field. I have a friend that has a 34" tube television directly on top of a belle klipsch, with no distortion. The tweeter is not that far away, and no problems.

[michael hurd]

It also depends on what sort of display that the poster is using, if he is using a rear projection unit, then there would be no problems if the speaker was on top of the television. As long as the weight is more or less spread out, there should be no issues with the top sagging. If it is a tube, well then you would want the woofer shielded at the very least.

[michael hurd]

I just quickly googled under "ceramic ring magnet", and came up with a few links.

http://www.magnetsource.com/Solutions_Pages/RINGSceramic.html

http://www.permanentmagnetco.com/roundmags.asp

Also, a quick check of the madisound webpage turned up 3 sizes of magnets, 3.7, 6.3, and 19.2 ounce.

[DrWho]

You can also use a metal can (as long as it conducts magnetism) and position it around the magnets as well...it works by deflecting the magnetism. Perhaps a smaller magnet in combination with a can might be in order.

[Jay L]

klipsch does have the magnets you need unless we just run out in the last couple weeks.

part #s are

158006M 50 OZ. you will need 2

158001M 20 OZ. qty of 1

158005M 9.4 OZ. qty of 1

i used 2 part clear epoxy from wal-mart to stick them together

[captain]

Parts ordered, I guess some one at Klipsch is working over time Thanks. Bought the last factory set of bucking magnet for a KLf-20 should do the trick.

Good thing love the sound and set up 7.1 all LegendsBad thing.I have to come up with a new excuse (wife) to replace my perfectly good 36 Proscan TV.

I appreciate all of youre help . Thanks.

[rosc2112]

DrWho wrote the following post at 05-25-2005 3:58 AM:

You can also use a metal can (as long as it conducts magnetism) and position it around the magnets as well...it works by deflecting the magnetism. Perhaps a smaller magnet in combination with a can might be in order.

[....]

I know this is an old thread, but maybe someone can elaborate on this? Any old steel can? Simply fitted over the magnet? How does it effect speaker performance?

I googled around a bit, but most of what I found about shielding, revolved around wrapping the whole speaker cab in wire mesh or foil. I've never heard of using a can to cap the magnet before, and the subject has become important to me, because those Cornwalls I found? I can't get within 2' of my tv! Not unless I really like green [grin]

[djk]

"revolved around wrapping the whole speaker cab in wire mesh or foil. "

Don't waste your time on that.

The bucking magnet needs to be about 80% the size of the main magnet.

A ring of smaller magnets will work too.

Determine which polarity to mount the magnets. They will want to push apart until they are a fraction of an inch from the main assembley, then they suck down.

The steel can covers this whole mess, by itself it does little.