This post was published 1 year 3 months 20 days ago.
It\'s is possible that the information within this article is now out of date or updated.

You know that buzz you get on your PC speakers or wired headset, or otherwise whenever you set your cell phone near it?  Yeah I think we all do.  Well fortunately it’s quite easy to fix, especially for those of you who know about electro-magnetic interference, this fix will come as no surprise.  But first a little background.

The reason this phenomena occurs is because your cell phone (in particular GSM band phones, aka phones from AT&T, T-Mobile, etc) checks with the cellular network about once every 55 minutes or so to see if it’s still in the area.  This is specifically the GSM band, which comes close to the frequencies of information sent over audio cables, essentially turning the audio cable into a antenna, which is thus transmitted into your speakers, creating the annoying buzz.  Fix after the break.

So how do you fix it?  Ferrite beads.  A ferrite can be thought of as a resistor only to high frequency electromagnetic interference instead of electricity.  You’ve probably seen them around before and may not have realized it.  There’s a picture of a ferrite in a plastic container on the left (it’s the little cylinder near the end of the cable).  You can typically find some of these laying around the house, or maybe you can hijack one of them from a cable you don’t use.  You can also buy them from places like Digi-Key or Mouser Electronics.

Placing is easy.  All you  have to do is place the ferrite on your speaker cable (or otherwise) close to the target.  So if you were protecting your speakers, you’d place the ferrite on the speaker cable very close to the speaker itself.  If you’re still getting a little buzz, you can wrap the speaker cable through the ferrite to create even more EMI resistance (especially useful if you have a ferrite too lightweight for the load).  Keep in mind that ferrites work by transforming the EMI into heat and dissipating it.  It’s unlikely a very high amount in even huge circumstances, but it’s a consideration to keep in mind.

More on Ferrites

[via Engadget]

Tyler (30 Posts) - Website | Twitter | Facebook