Microphone calibration files

kafercup

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I'm happy to see the app now recognizes my Dayton Audio iMM-6C. Will there be an option in the future to upload the specific calibration files for a microphone?
 

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Unfortunately @WiiM Support have not documented the file format they expect but have included examples from one vendor. Maybe we can deduct something from that?


That page doesnt suggest how wiim is applying the calibration, be it additive or subtractive.

There was a post that asked users to upload their mic cal files to help wiim improve compatibility with cal files, and from a quick look, many of the cal files provided were for imm6's and imm6c's.


On the one hand you'd expect Wiim to have figured out how the dayton mic calibration files work given so many people provided their dayton mic cal files to this thread, on the other hand, they might have just been looking at the format of the files rather than polarity.

I am trying to understand this situation, but many people are saying "Dayton support are wrong", can someone clarify in which way are they wrong? Are they wrong to suggest that their mic cal files should be added to the result, or are they wrong in the sense that the actual cal file is inverted from what measurement software would expect?

I have reason to believe the wiim is reading the imm6c cal file in the wrong polarity, because I note that the cal file drops off into negative number very quickly starting at 8khz and above, and every measurement I take of my speakers drops off a cliff at 8khz, making me think that the response error is being doubled rather than corrected.

If this is the case, it could be that every imm6c user here is potentially using an inverted calibration file for their RoomFit measurements and really skewing their results.
 
That page doesnt suggest how wiim is applying the calibration, be it additive or subtractive.

There was a post that asked users to upload their mic cal files to help wiim improve compatibility with cal files, and from a quick look, many of the cal files provided were for imm6's and imm6c's.


On the one hand you'd expect Wiim to have figured out how the dayton mic calibration files work given so many people provided their dayton mic cal files to this thread, on the other hand, they might have just been looking at the format of the files rather than polarity.

I am trying to understand this situation, but many people are saying "Dayton support are wrong", can someone clarify in which way are they wrong? Are they wrong to suggest that their mic cal files should be added to the result, or are they wrong in the sense that the actual cal file is inverted from what measurement software would expect?

I have reason to believe the wiim is reading the imm6c cal file in the wrong polarity, because I note that the cal file drops off into negative number very quickly starting at 8khz and above, and every measurement I take of my speakers drops off a cliff at 8khz, making me think that the response error is being doubled rather than corrected.

If this is the case, it could be that every imm6c user here is potentially using an inverted calibration file for their RoomFit measurements and really skewing their results.
I raised a ticket (#526422) about the missing WiiM documentation in this area, 6 months ago. Only answer I got from the Support was that they didn't understood what was missing.
 
That page doesnt suggest how wiim is applying the calibration, be it additive or subtractive.

There was a post that asked users to upload their mic cal files to help wiim improve compatibility with cal files, and from a quick look, many of the cal files provided were for imm6's and imm6c's.


On the one hand you'd expect Wiim to have figured out how the dayton mic calibration files work given so many people provided their dayton mic cal files to this thread, on the other hand, they might have just been looking at the format of the files rather than polarity.

I am trying to understand this situation, but many people are saying "Dayton support are wrong", can someone clarify in which way are they wrong? Are they wrong to suggest that their mic cal files should be added to the result, or are they wrong in the sense that the actual cal file is inverted from what measurement software would expect?

I have reason to believe the wiim is reading the imm6c cal file in the wrong polarity, because I note that the cal file drops off into negative number very quickly starting at 8khz and above, and every measurement I take of my speakers drops off a cliff at 8khz, making me think that the response error is being doubled rather than corrected.

If this is the case, it could be that every imm6c user here is potentially using an inverted calibration file for their RoomFit measurements and really skewing their results.
All calibration files describe the frequency response of the microphone. If WiiM were getting the polarity wrong and 5dB was being subtracted instead of added at low frequencies the result would be a massive bass boost from room correction. Dayton Audio customer service are probably as bad as customer service anywhere.
 
Correct, microphone "calibration files" are usually just microphone frequency response files. The measurement SW like REW or RoomFit automatically inverts the cal file which should result in a perfectly flat mic response.

However, IME Dayton factory calibration files may not be that reliable.

I had my Dayton EMM-6 microphone calibrated by a third-party (Cross Spectrum Labs) and you can see that this calibration is completely different to the factory calibration file:
index.php

The factory calibration looks noisy and almost random, unlike the one from Cross Spectrum Labs.
 
Correct, microphone "calibration files" are usually just microphone frequency response files. The measurement SW like REW or RoomFit automatically inverts the cal file which should result in a perfectly flat mic response.

However, IME Dayton factory calibration files may not be that reliable.

I had my Dayton EMM-6 microphone calibrated by a third-party (Cross Spectrum Labs) and you can see that this calibration is completely different to the factory calibration file:
index.php

The factory calibration looks noisy and almost random, unlike the one from Cross Spectrum Labs.
That factory cal looks strange. This is mine for a iMM-6C

1000005214.jpg

I think it is just fine.
 
That factory cal looks strange. This is mine for a iMM-6C

View attachment 26544

I think it is just fine.
It would be really great if Dayton improved their calibration in the meantime.

Note however that your graph vertical scale is about 40dB, and in addition the picture is vertically compressed too. This can hide a lot of details.

The graph in my previous post is only 20dB of vertical resolution, and expanded over a much taller picture. So a lot more detail of each response is exposed.
That means that the imprecision of the factory calibration of my mic is absolutely not as severe as it looks at first glance - i.e. it is usable, but the mic is just as accurate without it (actually more accurate in this case...)
 
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