How to dampen a magnetic field?

Question

I'm about to mount three 12" subwoofers into my car. They will be mounted in a triangular pattern, leaving two of the subwoofers about one foot away from the hard drives of a computer system I've installed in my car. How can I dampen the magnetic field to protect the disk drives, or would it even be necessary?

Answer 1

I wouldn't worry about the magnetic field too much, a foot is pretty large distance. The magnet structure of the woofers is designed to keep as much of the flux as possible at the voice coil where it is useful. Ever take apart an old hard drive? the magnets in the head actuator are pretty impressive, and they are a fraction of an inch from the disks.
Now vibration, might be an issue. The heads of a hard drive are flying extremely close to the disk, and are _somewhat_ susceptible to vibration, if they touch it rapidly damages the heads and disk. If you are playing your system loud enough to rattle the windows in my house when you drive by, you may be in danger of damaging the drive just from vibration. But if you do I'll just laugh. :-)

Answer 2

You are welcome to get a high u-metal as suggested, but the best thing would be to put it in what is called a faraday box (im not sure if the slow varying magnetic field would damage the hard drive, but just to be safe).

A faraday box is used by microwaves to shield the electromagnetic energy from getting out. I would be surprized if a hard drive does not already have a faraday box. Basically a Faraday box is just an enclosed metallic box with high permeability, stainless steel should do.

Answer 3

It sure will! Encase them in magnetic sheet metal. They will erase the hard drives.

Answer 4

There's a type of metal called mu metal that will shield magnetice fields ..

http://en.wikipedia.org/wiki/Mu-metal

Answer 5

not needed u can do it no hard disk damage