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Microphone Calibration

Raven Luni

Oct 15, 2011
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Greetings,

Obtaining a true frequency response for a microphone is something I've been wondering about for a while. Everything I've seen either talks about expensive equipment, anechoic chambers etc, or speaker design. I'm interested in a much broader frequency range than the audible and in a true rather than pleasant sounding response so thats not much use to me.

So I thought screw that and had a think about it for myself. The measuring part seems simple enough - either use a set of control frequencies or some white noise with a guaranteed even frequency distribution, then take the total energy for each frequency that is recorded and work out the equalisation from that.

BUT first, you'd need a source.......
 

davenn

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Sep 5, 2009
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and you are going to need an airtight and echo free chamber (anechoic chamber) of some sort, else your measurements will be tainted.

a respectable audio signal generator would be a good start. I havent seen sales for white noise generators, but Im sure they exist :)


Dave
 

Harald Kapp

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Nov 17, 2011
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You will have to take into account the characteristics of the speaker, too. The signal generator alone is no help if you don't have a speaker (or something similar) to convert the signal to sound. And the speaker is probably the worse part of the equation. Whereas a microphone can have a fairly linear behaviour over a wide range of frequencies, a speaker normally doesn't.You'll have to "subtract" (not exactly in the mathematical sense) the speaker's frequency response from your measurements.
How to calibrate a speaker and/or microphone is described e.g. here: http://www.daqarta.com/dw_0axx.htm

It might be cheaper to buy a calibrated microphone with a known charcteristic, e.g. http://www.linearx.com/products/microphones/m31/M31_3.htm

Harald
 
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