Trying to get a microphone to produce a signal

  • #1
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Main Question or Discussion Point

I removed a condenser microphone
From a sound meter. I plug it in a breadboard. But the Condenser microphone won't produce a voltage or signal. I tried yelling into the microphone. I tried Connecting a battery to circuit. Nothing I tried worked. Anyway to get microphone to pick up signal?
 

Answers and Replies

  • #2
phinds
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Any chance the mic is putting out far less voltage than the sensitivity of the meter that you are measuring it with?
 
  • #4
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The multimeter I have can measure as
Little as a millivolt I think. How do you apply bias voltage to the microphone?
 
  • #5
analogdesign
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Condenser microphones need bias (as Jim said).

This called "Phantom Power" and the bias comes through the microphone cable and is supplied by the mixer or the audio interface (typically only higher-end mixing consoles will provide phantom power.

Here is a Wikipedia article on Phantom Power that includes a schematic for how you can supply some to your microphone.

https://en.wikipedia.org/wiki/Phantom_power
 
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  • #6
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How high should the bias voltage be?
 
  • #7
analogdesign
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For professional audio applications the standard is 48V, although I think the standard has provisions for 24V and 12V. Other devices may have different requirements. Can you look up the datasheet for whatever microphone you have? If you can't find out, I would try a low voltage and slowly increase until the mic comes to life.

Hopefully you can identify the specific microphone because you also have to make sure you can accommodate its bias current requirements as well as voltage.
 
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  • #8
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How do I tell if microphone comes to life?
 
  • #9
analogdesign
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talk into it and see if the output voltage wiggles?
 
  • #10
jim hardy
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many condenser microphones use only a volt or two or three. I've seen some with watch batteries some with AA cells inside.
Some use around 9 volts per the Audio-Technica article below.

see
https://blog.audio-technica.com/what-is-bias-voltage/

can you figure out what the device you took it out of provided?
 
  • #11
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It was a Lv 6 sound meter I bought at
Walmart. I don't know the model.
 

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