Speaker too close to monitor

[headkaze]

I was pretty sure my speakers were far away enough to not effect the monitor in my cab, but have now realised there is a green tint in the corner when the screen is red. Is there any way I can stop this from happening? I'm using standard car speakers and an old 21" monitor.

[KDOG]

you could use bucking magnets to reduse its field
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3

[grantspain]

We had a equal problem on a machine we used to build,we resolved this problem by placing a metal shield around the speakers.But would it not be simple to just move the speakers.

[headkaze]

KDOG: That page is showing 0 results

grantspain: pretty difficult to move the speakers, theyre mounted quite securely and would be a major mess changing the position. Check out the image below. So what kind of "metal shield" did you use exactly?

[grantspain]

See what you mean about the positioning of the speakers.we used just a steel plate that covered the speaker in a u-shape,but after looking at your cabinet i think just a manual degauss would do the job.One thing to check-where you have the discoloring on the tube is it in a corner near one of the bolts that holds the tube to the frame?if so remove the bolt it might have become magnetised if that cures it just replace the bolt.

[headkaze]

I found an interesting read on the net..

My near field monitors are affecting the colors on my video monitor. What can I do to shield the speakers?

Despite a lot of folk lore and some very impressive sounding wisdom here on the net and in showrooms, there is effectively nothing that you can do to the speakers or the monitor, short of moving them away from one another, that will solve this problem.

The problem comes from the magnetic field created by and surrounding the magnets in the loudspeaker. It's possible to design a magnet that has very little external field, but it can be an expensive proposition for a manufacturer. If the magnets do have large external fields, the only technique that works is by solving the problem at the source: the magnet. Special cancelling magnets are used, sometimes in conjunction with a "cup" shield directly around the magnet.

You'll hear suggestions from people about placing a sheet of iron or steel between the speakers and the monitor. That might change the field, but it will not eliminate it. As often as not, it will make it worse.

You'll also here from people about shielding the speaker by lining the enclosure with lead or copper. This method is absolutely guaranteed to fail: lead, copper, aluminum, tin, zinc and other such materials have NO magnetic properties at all, they will simply make the speaker heavier and won't solve the problem at all. There is but one material that has a shot at working: something called mu-metal, a heavy, very expensive, material designed for magnetic shield that requires extremely sophisticated and difficult fabrication and annealing techniques. It's cost is far greater than buying a new set of speakers that does not have the problem, and it may not even work if the majority of the offending field is radiated from the front of the speaker, which you obviously can't shield

Try moving the speakers relative to your monitor. Often, moving them an inch or two is enough to cure the problem or at least make it acceptable. Sometimes, placing the speakers on their sides with the woofers (the major offenders in most cases) farthest away from the monitor works. [Dick]

[grantspain]

Interesting reading,when i worked for gamestec we had a machine called a gamesnet which had constant problems with the magnetic fields of the speakers,in the end the problem was resolved by a different type of speaker incorperating a shield to reduce the magnetic field, if you are in the uk go and see your local gamestec depot they will probably give you a couple of speakers for nothing(just beg).But i still think your speakers are far enough away from the tube to not give a problem-possibly you tube frame has become slightly magnetic.This might sound very strange but have you tried rotating your cabinet to see if the problem moves(sometimes there are magetic fields in the ground that cause problems-no i am not mad-try it).

[KDOG]

Sorry about the the link. Just type in bucking magnets in to the search at  http://www.partsexpress.com/?wt.svl=1