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How to measure the response of a mic?

radix

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I recently assembled a microphone-parts.com mic (the S3-12). I would like to measure it's response and sensitivity. I have a UMIK-2. My plan was to set these up next to each other and record both in REW and see how the S3-12. I have some KH80&KH750 that I was planning to use, likely from the MLP where I calibrated them (about 86cm from KH80s). For the cardioid, I'd use the UMIK in the 0* position and for the fig-8 and omni, I'd using it in the 90* position.

What do you think of this plan? Or other suggestions?

My main goal for this is to see what the response looks like and decide if I should use any EQ caps in it (which they provided). My initial testing is that they are a little bright for me and I want to knock off some of the highs, but I'd like to have a good way to measure them.

 

617

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Far from an expert, but I believe testing mics is about as complex as testing speakers.

I think the most practical approach would be to place a sort-of-linear speaker in front of your mics, and measure both your new microphone and a reference microphone in the same position. By comparing the two signals you should be able to calculate the response of your new mic.

One of the challenges with mic measurement is that reference microphones are almost always omni and many recording mics are cardioids or dipoles. Like with speakers, directivity is difficult to 'separate out' from the response, and one could argue much of the sound of a mic comes from directivity.

Measuring overall sensitivity is another matter but I suspect you are interested in tonality.
 

DVDdoug

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It seems reasonable to compare the corrected/calibrated UMIK-2 to the uncorrected response of another mic.

But in a room, a slightly different position or the directional characteristics of a cardioid or figure-8 mic will give different/unreliable results at higher frequencies.

As you may know, most studio mics aren't "flat", and most recording engineers don't seem to choose flat mics..

You'll probably find this video interesting if you haven't already seen it.
 

kemmler3D

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Agree with the above, you can get an idea by testing the new mic against a known/calibrated mic. But since the pickup patterns will be somewhat different, the exact position will never be quite exactly the same, etc... I would not put a lot of stock in small variations especially at high frequency.
My main goal for this is to see what the response looks like and decide if I should use any EQ caps in it (which they provided).
I think your proposed method is good enough for this goal.

On the other hand, you don't need an absolute reference to make this decision. Compare your vocal recordings to some references you like and see whether the mic seems too bright on that basis. "If it sounds good, it is good".
 
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radix

radix

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Compare your vocal recordings to some references you like and see whether the mic seems too bright on that basis. "If it sounds good, it is good".

Yep, that was going to be my main "calibration" but I wanted some sort of objective measurement to keep my bias in check.

As the UMIK-2 is an omni, and I can select an omni pattern on the S3-12, perhaps that would be my best test pattern.

I will, of course, also test it on various sources. As I'm not a soprano, I'll test it against guitar high notes to get up to 7k & harmonics through it, which in practical terms is the highest pitches I'd be recording.
 

Dave Bullet

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A bit late to the party, but if you have response curves for known drivers, you can subtract in REW against the same driver (and baffle conditions) to generate your own calibration file. I had reasonable success doing this for an uncalibrated Behringer ECM8000. It compared favourably to my UMIK-1. Now whilst these aren't cross spectrum labs level calibrations, it was at least reliable and likely proved my MiniDSP provided UMIK-1 wasn't too far off "spec".
 

Blumlein 88

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A bit late to the party, but if you have response curves for known drivers, you can subtract in REW against the same driver (and baffle conditions) to generate your own calibration file. I had reasonable success doing this for an uncalibrated Behringer ECM8000. It compared favourably to my UMIK-1. Now whilst these aren't cross spectrum labs level calibrations, it was at least reliable and likely proved my MiniDSP provided UMIK-1 wasn't too far off "spec".
Yes this works with care. I've calibrated some recording microphones well enough they are in close agreement with the Umik-1 and each other. It works over different conditions of measurement. Yes, not equal to CrossSpectrum labs or what someone like Earthworks does. More than good enough for many, many applications someone might have.
 
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