Re: Capturing EM interference with a microphone

Jasen Betts wrote: 
On 2005-11-04, jh <no@xxxxxxxxxx> wrote:


The only problem is, all of these great interference-caused phantom sounds were almost drowned out by the actual normal sound produced by the fans, hard drive, etc. in the computer. Needless to say, the microphone was quite adept at recording these sounds. 


the reason for that is that the dynamic microphone has a voice coil (like in a
loudspeaker) anf that coil picks up all the electromagneic interferance (EMI)
inside your computer.


So my question is this: is it possible to build a device, or modify a microphone, so that it picks up ONLY the electromagnetic interference, but no actual sound?


You'll need to shield it against EMI. while not blocking too much sound that that won't be easy. basically you need to surround it with a conductive
shell, electret mikes (like the "ctrappy lapel mike") are constructed that way.

Bye.
   Jasen

In fact the "crappier" the microphone the more EMI it will pick up!
.

Relevant Pages

  • Re: Capturing EM interference with a microphone
    ... >> sounds were almost drowned out by the actual normal sound produced by ... >> microphone was quite adept at recording these sounds. ... >loudspeaker) anf that coil picks up all the electromagneic interferance ...
    (sci.electronics.basics)
  • AES AWARDS
    ... API racks, some of which caused power supply problems. ... This one is always a real tossup, but I kind of liked the Core Sound ... tetrahedral microphone array, the AmbiMic. ... modern Dolby Digital EX systems. ...
    (rec.audio.pro)
  • Re: Built-in Mic and MS Word
    ... Recording sound in a lecture hall is always going to be a challenge. ... The iBook doesn't have a Microphone port: ...
    (microsoft.public.mac.office.word)
  • Kludges 2009 AES Show Awards
    ... This is not only the first time I have given an award to a plug-in, ... Ecstatic Electric was showing off a wooden horn microphone. ... WORST SOUND IN SHOW ...
    (rec.audio.pro)
  • Re: Kludges 2009 AES Show Awards
    ... This is not only the first time I have given an award to a plug-in, ... Ecstatic Electric was showing off a wooden horn microphone. ... WORST SOUND IN SHOW ...
    (rec.audio.pro)