Cockpit stereo speaker EM shielding for autohelm

[samwise]

We are planning a cockpit speaker installation to provide a stereo feed into the cockpit. One speaker will take a switchable feed from the VHF and double as a radio cockpit speaker, the other will pick up from the stereo. The problem is that speaker location choice is limited and it looks impossible to fit one or the other where the strong magnetic influence will not adversely affect the autopilot fluxgate compass. Our AP is a Raymarine 2000+ which is a single unit device so that we cannot move the fluxgate to another location.

Is there a way to shield one or both speakers? As far as I know there are no kits available other than very basic plastic covers for the speaker back that will not do the job.

I hasten to add ( in anticipation of the likely reaction from some Forumites) that we have no intention of inflicting our music etc on marina or anchorage neighbours, but the installation would be a comfort on long passages.

Any ideas welcomed.

 

[FullCircle]

Try this page. It mostly makes sense - A magnet shield wrap.....

http://www.lessemf.com/faq-shie.html#speakers

 

[SailBobSquarePants]

There are a host of magnetically shielded marine speakers, from Jensen, Alpine, Clarion, Pyle, etc. Any of these will have a fixed magnet that will reverse the field of the driver magnet, thus negating most of the magnetic affect at a distance. I would trust the higher-end models to be better at this than the lower end, so if you have the cash my preference would be:

http://www.outdoorgb.com/p/alpine_m...urrency=GBP&country=GBR&SelectedBundle=109189

Of course, you could have used the YBW search function...

http://www.ybw.com/forums/showthread.php?t=1996

 

[SailBobSquarePants]

Almost forgot, you can make your own shield enclosures should you wish:

http://www.ehow.co.uk/how_7349197_magnetic-field-shielding_-tutorial.html

 

[vyv_cox]

At the aft end of the cockpit you can see one of our cockpit speakers. Immediately adjacent to it is the screwed socket for the tillerpilot. This setup has existed for more than ten years, with no effect whatever on the accuracy of the steering under tiller pilot. The speakers are nothing special and not shielded in any way as far as I know.Assuming the fluxgate of the pilot to be in the wider base end, it is around 6 inches from the speaker.

This shows the TP in action but with its sunshade on.

 

[samwise]

Try this page. It mostly makes sense - A magnet shield wrap.....

http://www.lessemf.com/faq-shie.html#speakers

Very helpful guys. I think we have a result. Many thanks Full Circle