Electrostatically-coupled Noise Causes Buzzing Mic

When a buzzing microphone started interfering with services at his local church, Engineer Dick Neubert realized he wouldn’t be able to count on divine intervention to solve the problem. 

As he describes in his EDN Tales From the Cube installment “Silence in the Sanctuary,” Neubert describes his successfull efforts to locate (and mitigate) the offending party

The solution? A custom Faraday Cage, of course. Problem resolved.



  1. themagni – compact fluorescent lamps do not use external ballasts. They have an internal switch mode boost converter which give off a lot of noise.

  2. This seems like a solution where you are masking the problem instead of making it go away. Unless you’re working in RF, then “Faraday Cage” is usually the wrong answer.
    It could be a problem with the wiring itself – you should never get a buzzing noise in auxiliary equipment from lighting. I would get an electrician (from another firm) in to confirm that the wiring is done correctly. I would do this today. There’s a good chance that either the ballasts are wired in backwards (with a hot ground), are underpowered for the lights, or are not isolated from the other circuits properly. Since there’s a potential for either fire or shock, this should be looked at quite seriously very quickly.

Leave a Reply

Your email address will not be published. Required fields are marked *