UMIK-1 or any USB MIC unsuitable for timing measurements?

[levimax]

"It is provided with a unique calibration file based on the serial number to insure an accurate measurement."

So what part of the above statement indicates anything other than unique file? Unless they just randomly futz with them to make it look good they must be measuring each one. I've examined several and no two are the same.

I've done the same for the Dayton EMM-6. No two are the same. I've got an IMM-6 which cost me $15, but is a little more now. I've examined several of those cal files and no two are the same.

The UMIK language is super fuzzy to me an could mean anything... kind of like what does "Remastered from master tapes" mean.

I wonder why so many people online claim they are "batch" calibrated if they had nothing to base it on?

 

[Blumlein 88]

Dayton emm-6 calibration is so full of noise you may be better off without it. Maybe with 1/1oct smoothing...

Red trace is the supplied calibration file for an EMM-6 I purchased. Blue is 1/1oct smoothed. Those who know what a mic cal should look like would throw away the garbage supplied with EMM-6.
View attachment 360429

How do you come to that conclusion? Especially past 2 khz you would expect some up and down response.

 

[Blumlein 88]

The UMIK language is super fuzzy to me an could mean anything... kind of like what does "Remastered from master tapes" mean.

I wonder why so many people online claim they are "batch" calibrated if they had nothing to base it on?

Don't know, point me to someone saying that with any indication beyond a guess. People claim many things. Some of them are even true.

The Umiks have over 600 measurement points and the Dayton just over 250 points. The only difference I see in the statements is Dayton says they use a B&K which is good, but Umik doesn't specify.

 

[Blumlein 88]

Here is the difference in a Umik 1 cal file and the Dayton IMM6 (the little measuring mic for plugging into phones with TRRS jacks).

Here is the difference in two IMM 6 files.

 

[dcibel]

How do you come to that conclusion? Especially past 2 khz you would expect some up and down response.

Those who know what a mic cal should look like...should expect something without the noisy lumps, like what you get with UMIK-1. I've compared EMM-6 to a couple other mics, the noise in the calibration is only making measured results worse.

UMIK-1 random cal file for context.

 

[levimax]

Don't know, point me to someone saying that with any indication beyond a guess. People claim many things. Some of them are even true.

The Umiks have over 600 measurement points and the Dayton just over 250 points. The only difference I see in the statements is Dayton says they use a B&K which is good, but Umik doesn't specify.

Lots of discussion not much in the way of verified facts. I found one link that is kind of interesting, it doesn't speak directly to the issue but it looks like there can be pretty big difference between the same model of Mic even using the supplied calibration file. https://www.mtg-designs.com/tips-tricks-tests/measurement-mic-tests/fr-mic-compare

Based on this it appears the Cross-Spectrum files for only $15 or so extra are the way to go.

 

[Emlin]

"It is provided with a unique calibration file based on the serial number to insure an accurate measurement."

So what part of the above statement indicates anything other than unique file? Unless they just randomly futz with them to make it look good they must be measuring each one. I've examined several and no two are the same.

I've done the same for the Dayton EMM-6. No two are the same. I've got an IMM-6 which cost me $15, but is a little more now. I've examined several of those cal files and no two are the same.

I just did a quick look checking adjacent serial numbers. If batch tested you would think they might have the same file. They do not have the same file.

I don't know much on this subject, but I do know that a calibration file should not be based on the mic's serial number, but on its measured performance.

And that that will ensure, not insure, accurate measurements.

 

[Blumlein 88]

As recently as a few weeks ago I've seen an AVS post saying Umik 1s are batch calibrated and Umik 2 are individual. That has never been the case or never said by Umik. Back around 2009 and 2010 were different forums claiming Dayton's were batch calibrations. With some citing CSL as saying that was the case. Yet CSL has not claimed that only that they will cal to a higher standard, and that other cals by the sellers have some issues with less than best techniques. The MTG link above casts doubt on CSL being correct as they tend to an unexpectedly uptilted cal at the upper end of the frequency range.

I'm in no position to say what is most correct. It appears the batch calibration idea is an old one that persists without any evidence. How good the cals are is another matter. If one thinks the Dayton is too bumpy, using 1/6 octave smoothing will take care of it. Or one could modify the file to do smoothing. With care one could calibrate one against the other, but you still have no reference for absolute accuracy. In the upper frequencies you can have bumpiness from resonances and shapes of the microphone housing. I don't see huge differences that would effect how these microphones can be used practically. If one wants superior accuracy and calibration it will cost you. An Earthworks is about the bottom of that rung and it goes up from there. If I had access to an Earthworks I'd use it to cal my own cheaper measurement microphones.

A member here has shown several times that using the Umik cal files his Umik 1 is a very close match for his Earthworks. Other than that who knows which is the best calibrated sub-$100 measurement microphone. One thing it appears is the batch idea is not true for the ones from Umik, or Dayton.

 

[levimax]

I don't know much on this subject, but I do know that a calibration file should not be based on the mic's serial number, but on its measured performance.

And that that will ensure, not insure, accurate measurements.

Maybe I am too cynical but the UMIK language could mean many different things. Less cynical, it could just be a language barrier thing.

 

[Blumlein 88]

I don't know much on this subject, but I do know that a calibration file should not be based on the mic's serial number, but on its measured performance.

And that that will ensure, not insure, accurate measurements.

I don't understand your thinking here. The reason for a serial number is to match your microphone with the measurement they made of it. What could be the reason otherwise? The cal isn't based upon the serial number it is the serial number being a way to match your particular microphone to its particular measurement.

 

[Blumlein 88]

Maybe I an too cynical but the UMIK language could mean many different things. Less cynical, it could just be a language barrier thing.

Give three different interpretations of their statement. I don't see any ambiguity. They could tell us what their reference mic is, and if they use a standard device for checking like Dayton tells us, but that doesn't indicate anything I can see other than they in some way measure each mic and give you the file for it.

 

[Emlin]

I don't understand your thinking here. The reason for a serial number is to match your microphone with the measurement they made of it. What could be the reason otherwise? The cal isn't based upon the serial number it is the serial number being a way to match your particular microphone to its particular measurement.

But it does actually state that the calibration file is based on the serial number...

 

[levimax]

As recently as a few weeks ago I've seen an AVS post saying Umik 1s are batch calibrated and Umik 2 are individual. That has never been the case or never said by Umik. Back around 2009 and 2010 were different forums claiming Dayton's were batch calibrations. With some citing CSL as saying that was the case. Yet CSL has not claimed that only that they will cal to a higher standard, and that other cals by the sellers have some issues with less than best techniques. The MTG link above casts doubt on CSL being correct as they tend to an unexpectedly uptilted cal at the upper end of the frequency range.

I'm in no position to say what is most correct. It appears the batch calibration idea is an old one that persists without any evidence. How good the cals are is another matter. If one thinks the Dayton is too bumpy, using 1/6 octave smoothing will take care of it. Or one could modify the file to do smoothing. With care one could calibrate one against the other, but you still have no reference for absolute accuracy. In the upper frequencies you can have bumpiness from resonances and shapes of the microphone housing. I don't see huge differences that would effect how these microphones can be used practically. If one wants superior accuracy and calibration it will cost you. An Earthworks is about the bottom of that rung and it goes up from there. If I had access to an Earthworks I'd use it to cal my own cheaper measurement microphones.

A member here has shown several times that using the Umik cal files his Umik 1 is a very close match for his Earthworks. Other than that who knows which is the best calibrated sub-$100 measurement microphone. One thing it appears is the batch idea is not true for the ones from Umik, or Dayton.

The data in the link I posted, https://www.mtg-designs.com/tips-tricks-tests/measurement-mic-tests/fr-mic-compare while far from conclusive, which shows the Cross Spectrum calibration files to be excellent, while the Dayton and UMIK provided files to be quite variable (even with a sample of 2) could most easily be explained by "batch testing" for the calibration. Of course there could be other explanations but sometimes the most obvious explanation is correct.

 

[Blumlein 88]

But it does actually state that the calibration file is based on the serial number...

Tell me how that works? How does the serial number create the calibration. What process are you holding in your mind in how this is done?

 

[Emlin]

Tell me how that works? How does the serial number create the calibration. What process are you holding in your mind in how this is done?

It only works if they batch test, and that is the point here.

 

[levimax]

Give three different interpretations of their statement. I don't see any ambiguity. They could tell us what their reference mic is, and if they use a standard device for checking like Dayton tells us, but that doesn't indicate anything I can see other than they in some way measure each mic and give you the file for it.

The file is based on the serial number unknown relationship
The file is based on the Mic with that serial number
The file is based on the average of the batch that the Mic with that serial number was produced in
The file is randomly assigned to that serial number

 

[Blumlein 88]

It only works if they batch test, and that is the point here.

I have no idea what you are thinking. I have confirmed a one digit difference in the serial number is a completely different cal file. So they aren't doing batches of 100 and giving them all the same file. This is true of Umik and Dayton. The accuracy of their process is a different issue, but there is no indication of batch testing.

 

[Blumlein 88]

The file is based on the serial number unknown relationship
The file is based on the Mic with that serial number
The file is based on the average of the batch that the Mic with that serial number was produced in
The files is randomly assigned to that serial number

So you think they go to the trouble of batch testing, and then scramble the SN's randomly so people don't know it.

BTW, how do you batch test mics like this? You stick ten up and do it all at once and average. You test 10 one at a time and average the results for that group. You do realize since they measured it would be easier to just use the results for each mic. The batch testing idea would be more trouble to them. If I'm guessing, I'd guess CSL has the more accurate calibration, but I don't see much reason to think these others are not individually done.

 

[Emlin]

I have no idea what you are thinking. I have confirmed a one digit difference in the serial number is a completely different cal file. So they aren't doing batches of 100 and giving them all the same file. This is true of Umik and Dayton. The accuracy of their process is a different issue, but there is no indication of batch testing.

One digit is all you need to move from one batch to another.

Look, I suspect they are all individually tested, but I cannot tell that from their statement as it is far from definitive.

 

[dcibel]

FWIW I use a Line Audio Omini1 mic, which is not calibrated by a file, but rather the mics are passively adjusted to match an Earthworks reference. I found it to be within 1dB of a calibrated Dayton Omnimic, good enough for my use, and with the added benefit that I don't have to make sure I load in some calibration file, just plug and play (err..record). If I really wanted to, I could create and use a calibration file for the mic to make it match perfectly with the response of Omnimic, but for loudspeaker design, you will find the mic clip and boom stand will influence the response just as much, I've made perfectly well enjoyable speakers without the need for laboratory NIST traceable calibrations of equipment, as I'm in full control of adjusting the target curve to meet my preferences. Within 1dB