How to magnetically shield a speaker????


Help needed!!! Does anybody know how to magnetically shield a TV placed right above the floorstanding center speaker? The TV is on a firm movable platform (can go up to 4 feet high) with my center speaker right under it. I haven't chosen a projector yet, so I'm going to use my TV meanwhile. I saw a couple of links on this subject where they recommended to put the TV/monitor in a metal cage - quite a horrible vision to me. Is it possible to to obtain the same results using some thin foil or sheet? Thanks in advance. Mike.
michaelstarodoubtsevda45
A thin sheet of any metal with relatively high permeability (or magnetic susceptibilty) should help resolve your problem. Mild steel is one option but may not be enough, depending on the strength of speaker magnets and proximity to the TV. If you want better shielding, there are special alloys like "mu metal" and NETIC with very high permeability that are much more effective than mild steel. You can buy these alloys in thin foil sheets too. For info on such alloys, check out www.mushield.com or www.magnetic-shield.com (?). Don't know what the permeability of the "TI sheild" mentioned above is, so I can't say how it compares. But I do know that for shielding sensitive electronic instrumentation, mu metal works very well. Be warned, however, that even small sheets of these alloys can be pricey. (There might be other A-goners willing to go in on a group purchase for a larger sheet to reduce per unit costs.) Fully enclosing the source of the magnetic field (e.g., lining the inside of the speaker) is definitely preferable, but you might get by using a thin sheet of the "good stuff" between the TV and speaker. Hope this helps. Don
Try this. Once you have placed the TV and the speakers in the room, don;t move then. Turn the TV on and off at least 10 times in about a 5-10 minute period. See if the distortions go away.
Albertporter, great site! Man, the noodlers could have a field day with his stuff! Thanks :-)
A piece of steel or iron will have enough ferromagentic material to shield your tv. Don't use aluminum or tin. Put the steel/iron between the tv and the speaker and you will have no problem. Try it with a Cast iron pan from the kitchen if you want a proof-of-concept.
Texas Instruments makes a heavy metal material called TI shield, it is designed to do just what you are asking about. It is available from Mike Percy audio products. If I remember correctly, I paid less than $20.00 for a one foot square section of this. You can download a PDF file of all the data at his web site: http://www.bainbridge.net/percyaudio