selfmade magnetic shielding?

[OliverB]

Hi, with my current setup and room layout I might not be able to move speakers and amp more than 5 inches away from my 35inch CR TV. Not perfect in any way, but until we can afford the flat screen to hang on the fireplace that's in the middle of the wall.....

So, my center speakers is shielded, my front speakers are too, but they still recommend to place them at least 8 inches away, and my amp is not shielded in any way I'd guess.

Is it possible to build some kind of magnetic shield to prevent damage? I have no idea how a magnetic shield works, so sorry if this is a silly question...

Thanks!

Oliver

 

[jimmit]

I'm certainly no expert but my understanding of speaker magnetic shielding -- at least the overwhelming majority of it -- is that it is accomplished by means of a magnet which essentially neutralizes the magnetic field of the speaker magnet. The neutralizing magnet is placed inside the speaker at the time of manufacture. If you were to try to retrofit your speaker in this fashion, I suspect you'd have to know exactly what size/shape/power of magnet and where to place it inside the speaker.

I've heard that magnetic shielding can be accomplished by an actual metal shield but I'm not sure how this would be accomplished. Perhaps someone else has had experience in this area. Good luck.

 

[Tubes4Life]

There is simply a metal cap that encloses the magnet assembly on the speaker. what this does is it channels the magnetic flux through the "shield" rather than letting it go in free air.

 

[brian32672]

Here is something you may want to read...
http://www.lessemf.com/faq-shie.html#speakers

 

[Tubes4Life]

Here is something you may want to read...
http://www.lessemf.com/faq-shie.html#speakers

Excellent find, brian

 

[brian32672]

Actually there are other methods, mainly a cancellation magnet over the driver magnet...

 

[Tubes4Life]

that probably would suppres the field enough to cause a severe drop in the speaker's effeciency. you dont want to try and eliminate the field, as it is necessary for the speaker to operate. you just want to keep it away from anything it would affect...

 

[brian32672]

that probably would suppres the field enough to cause a severe drop in the speaker's effeciency. you dont want to try and eliminate the field, as it is necessary for the speaker to operate. you just want to keep it away from anything it would affect...

I have to disagree, here look at post #16 here http://forums.audioholics.com/forums/showthread.php?t=12810

These are mine, and they run quite well, and are super efficient at 96db spl...

 

[Tubes4Life]

ive never seen shielding done that way. very cool. so the backplate seperating the magnets seems to keep enough of the field around the voice coil...

 

[j_garcia]

that probably would suppres the field enough to cause a severe drop in the speaker's effeciency. you dont want to try and eliminate the field, as it is necessary for the speaker to operate. you just want to keep it away from anything it would affect...

Bucking magnets, when properly selected, have almost no affect on the speaker's performance.

 

[OliverB]

some great info here, thanks! Now I'm mostly concerned about the amp, a Denon 3805 which sits just a couple inches away from the TV, on the left. So the power supply - which I'd guess is the most "dangerous" - is as far away as possible, since it's in the left side of the amp.

I don't see any distortion of the picture like I had once years ago when I placed a bass speaker on top of the TV while building speakers. Made for an interesting effect..... (don't try this at home though)

I've noticed for a while that when the TV just shows black, there's a narrow greenish tinted stripe going down the left side. My old amp, a mission cyrus II with extra power supply, was also on the left, but on the floor. Don't know if there's a relation?

Thanks for the links, interesting reading!

Oliver