Cancellation Magnets- How big?

[Michael Duffy]

I have a pair of Dana Audio speakers that I want to use near a monitor. I
heard you can attach (glue?) a pair (one each speaker) of magnets in reverse
to the woofer magnets and then they can be close or near the monitor
(computer). Do you have to also do the tweeters? The woofers are 6.5. What
size magnets? Parts Express sells about twelve different sizes. Thanks.

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Michael Duffy

[Richard D Pierce]

In article >,
Michael Duffy > wrote:
>I have a pair of Dana Audio speakers that I want to use near a monitor. I
>heard you can attach (glue?) a pair (one each speaker) of magnets in reverse
>to the woofer magnets and then they can be close or near the monitor
>(computer). Do you have to also do the tweeters? The woofers are 6.5. What
>size magnets? Parts Express sells about twelve different sizes. Thanks.

Unfortunately, there's no exact relation between parameters such
as size of the magnet structure and the size of the reverse
magnet needed to effectively cancel the external field. If you
had a wide variety of pre0charged magnets available, then you
could experiment. A good emprical test is that the right size
magnet is that which, when brought in contact with the rear
plate of the driver's magnet assembly, has as close to a zero
net attraction/repulsion as possible. Oftentimes, this ends up
being about 2/3 of the size of the magnet used in the driver,
which for a typical 6.5" driver is on the order of about 8-9 oz
or so.

The magnets are cheap enough, you might want to try a couple of
different sizes.


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| Dick Pierce |
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