Shielding Drivers

[audioPT]

Hi all!

I've some woofers and tweeters that I want to use in a Home Cinema application.
But there is a problem: They aren't shielded.
If I use them, the TV set will be like a rainbow 😀

So, there is anythink I can use to isolate the magnetic field?

Thanks in advance for some reply!

Pedro Martins

 

[mrfeedback]

Pedro, take a look at typical shielded drivers and you will see that the shieling is a heavy iron cup placed over the back of the magnet and touching to the basket.
It should not be too hard to find something suitable if you look around.

Eric.

 

[planet10]

take a look at typical shielded drivers and you will see that the shieling is a heavy iron cup placed over the back of the magnet and touching to the basket.

A typical shielded driver has a metal can over the bucking magnet + the magnet. It is the extra magnet that does most of the job by focusing the field into the interior of the motor.

If you take two drivers and push them togther magnet-to-magnet they will resist and then when you get them really close they suck togther. You don't need the speaker attched to the 2nd magnet, but it points out that a closely coupled push-push pair has a high degree of natural shielding.

Approach you monitor with a single driver. Then do it with a pr magnet-to-magnet.

dave

 

[audioPT]

🙂

Oki!
I'm going to try your suggestions.

Thanks!

Pedro Martins

 

[thylantyr]

I'm going to line the inside of my midrange and tweeter chambers
with MuShield, 10 mil thick high permeability foil.

http://www.mushield.com

 

[cyclotronguy]

Sheet iron is a lot cheaper! You just use more.

Cyclotronguy

 

[planet10]

I'm going to line the inside of my midrange and tweeter chambers
with MuShield, 10 mil thick high permeability foil.

Keep in mind that i have some of this stuff in the Trading Post that i am selling off.

http://www.planetsofta.com/mumetal.html

dave

 

[thylantyr]

Does this mumetal or mushield actually work?
I'm just taking their word that it will work after
talking to their engineer - lol but in the real world? who knows.

 

[cyclotronguy]

Mu-metal works just fine. You don't however just place it as a barrier and hope for the best. Mu-metal redirects lines of magnetic flux, so it will need to be oriented in such a manner that it makes a complete magnetic circuit.

Cyclotronguy

 

[Sangram]

A typical shielded driver has a metal can over the bucking magnet + the magnet. It is the extra magnet that does most of the job by focusing the field into the interior of the motor.

If you take two drivers and push them togther magnet-to-magnet they will resist and then when you get them really close they suck togther. You don't need the speaker attched to the 2nd magnet, but it points out that a closely coupled push-push pair has a high degree of natural shielding.

Approach you monitor with a single driver. Then do it with a pr magnet-to-magnet.

dave

Sorry for pulling out this dinosaur.

Dave: two Qs.

1. How close do the magnets have to be? Some drivers have huge magnets. They have major repelling force when used back-to back.

2. What about tweeters? Back-to-back may not be feasible....

 

[chris229]

Mu-metal works just fine. You don't however just place it as a barrier and hope for the best. Mu-metal redirects lines of magnetic flux, so it will need to be oriented in such a manner that it makes a complete magnetic circuit.

Cyclotronguy

all high perm metals do the same thing. Redirect the magnetic flux. Iron steel would work just fine too

 

[planet10]

1. How close do the magnets have to be? Some drivers have huge magnets. They have major repelling force when used back-to back.

They need to be right together. You have to push the magnet thru the repell zone and usually when the get close enuff they attract (at least a bit). Crazy glue should work to hold them together.

dave