Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 21-09-2014, 12:20   #16
Registered User

Join Date: Dec 2010
Location: London, Ontario
Boat: MacGregor 25', Columbia 26 Classic
Posts: 347
Re: New Speakers and Old Compass

Quote:
Originally Posted by mcerdos View Post
Hmm? I thought since 304 stainless sheeting was non-magnetic (unless heated), it would serve nicely as a shield. Am I wrong?

The obvious choice would be to use iron but this is going to disintegrate and will be flush mounted in an area where it will be difficult to evaluate.
If the material is non magnetic, the magnetic field from the speakers will not be stopped by it. You need something that will contain or dampen most of the field but won't affect the compass itself.
__________________

__________________
frank_f is offline   Reply With Quote
Old 21-09-2014, 13:17   #17
Registered User
 
MBWhite's Avatar

Join Date: Apr 2012
Location: Illinois
Boat: Hurley Alacrity
Posts: 370
Re: New Speakers and Old Compass

Quote:
Originally Posted by mcerdos View Post

The obvious choice would be to use iron but this is going to disintegrate and will be flush mounted in an area where it will be difficult to evaluate.
Personally I'd just spray the cans with a couple of coats of cheap spray paint, if you wind wire around the first tin can do that first before painting but even cheap paint should provide enough corrosion protection for a location deemed safe enough for speakers. You can also get galvanized steel flashing in 6" wide rolls, Home Depot sells it in 10' X 6" rolls and you might try rolling up 5' for each speaker.

Also, I just had this crazy thought but you could get a cheap boy scout compass and put it on the ground and place the speakers on the ground where the distances are close to how they are mounted and experiment with the speaker orientation to see if you can affect the field that way, maybe if you rotate one or both you can get some magnetic cancellation to happen. Just a thought, probably won't do anything but would be a simple 10 minute exercise to experiment with. It would also make it easy to see if any shielding you do will have an effect.
__________________

__________________
MBWhite is offline   Reply With Quote
Old 21-09-2014, 13:56   #18
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,037
Re: New Speakers and Old Compass

Mark-
As I recall, mu metal is what is used in commercial magnetic shielding. It is a metal sheet that has a very high magnetic attraction, so it absorbs magnetic fields (energy) and prevents them from affecting whatever is on the other side of the mu metal. Stainless steel is a weak magnetic attraction at best, you want something that leaps to the magnet and soaks it all in.
Mu metal suppliers can be found on the web. Some quite pricey, others infest alibaba. I would expect that any "loud" or "powerful" speakers would be more problematic, because they'll be using bigger stronger magnets to handle high volumes. The old speakers may have been chosen for economy, making that less of a problem.
If you do decide to go speaker shopping, take a hand compass along with you, and use that to check them out in the store.
__________________
hellosailor is offline   Reply With Quote
Old 21-09-2014, 14:47   #19
Registered User
 
mcerdos's Avatar

Join Date: Jan 2011
Location: Full time cruiser
Boat: Amel Super Maramu 53
Posts: 187
Re: New Speakers and Old Compass

Quote:
Originally Posted by frank_f View Post
If the material is non magnetic, the magnetic field from the speakers will not be stopped by it. You need something that will contain or dampen most of the field but won't affect the compass itself.
Such as?
__________________
All the best,
Mark
www.creampuff.us
mcerdos is offline   Reply With Quote
Old 21-09-2014, 14:54   #20
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,037
Re: New Speakers and Old Compass

Such as...wait for it...mu metal.(G)
__________________
hellosailor is offline   Reply With Quote
Old 21-09-2014, 16:07   #21
Registered User

Join Date: Dec 2010
Location: London, Ontario
Boat: MacGregor 25', Columbia 26 Classic
Posts: 347
Re: New Speakers and Old Compass

Quote:
Originally Posted by mcerdos View Post
Such as?
Like I said back on post #8, mu metal or a Faraday cage.
__________________
frank_f is offline   Reply With Quote
Old 21-09-2014, 16:20   #22
Registered User

Join Date: Dec 2010
Location: London, Ontario
Boat: MacGregor 25', Columbia 26 Classic
Posts: 347
Re: New Speakers and Old Compass

Quote:
Originally Posted by mcerdos View Post
Such as?
Try this link:
Magnetic shielding film MCF5 3 Linear Feet - - Amazon.com

Hopefully that worked correctly.
__________________

__________________
frank_f is offline   Reply With Quote
Reply

Tags
compass

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
S hemisphere compass to N hemisphere compass blewett_john General Sailing Forum 7 07-11-2013 07:49
Wiring Cockpit Speakers to Existing Stereo with 4 Speakers Patrick_DeepPlaya Marine Electronics 10 30-10-2012 19:18
Neighbors SSB Powers Lights and Speakers jacob30 Electrical: Batteries, Generators & Solar 10 13-01-2012 11:24
New Speakers Installed ! Ahhh, Stereo . . . Butler Off Topic Forum 0 23-07-2011 23:20
Compass Deviatrion-Compass Card Paul Bradbury General Sailing Forum 6 05-02-2006 15:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:54.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.