Calibration Microphone

[alin_im]

Umik's have individual cal files for each mic. The 90 degree file is a calculated file based upon the size of the capsule and other factors. So that correction curve is the same for all of their microphones. They adjust the 0 degree file by combining those values with the 90 degree difference values. Since the Dayton looks nearly identical and uses a 6 mm capsule just like the Umik, the off axis change should be the same or nearly so.

I took the Umik 90 degree file (which I have for my Umik) subtracted 0 and 90 degree responses to obtain the difference. I then applied the same level of correction to the Dayton cal file. There is no correction until nearly 1500 hz and very little until 2500 hz and higher. I did some averaging, rounding etc to fit the Umik file to the Dayton file as the Umik has more data points. The Umik goes out to 3 decimal places while Dayton's is only one decimal place. So it should be about right, certainly in the right direction and approximate amount of correction.

Understood, sounds logical.

I will try what MAB said as well and maybe the guys at Spectrum Labs will send me some calibration files from other Mics, but at this moment I will just use what you produced.

So the idea is to measure 0 degrees for speakers etc and 90 degrees for room, correct?

 

[alin_im]

Hi all, coming back with some results from the calibration files of the Dayton Mic.

Using MAB methodology, I have tried the 90 degrees calibration file from Blumlein 88. I am not sure, but the formula to calculate the 90 calib file might have been a substraction instead of an addition. Please correct me if I am wrong, but I have reveresed the formula, and now the 90 degree response (with my 90 degree calib file) is the same as the 0 degrees response (with the original 0 degree calib file).

Attached you have all 3 calibration files and REW file.

Please let me know if the reversed formula is correct.

Red & Orange - 0 degree with 0 degree calibration file
Green & Yellow - 90 degree with 0 degree calibration file
Blue & Mint green - 90 degree with 90 degree calibration file from Blumlein 88
Purple & Light Blue - 90 degree with 90 degree calibration file from Blumlein 88 with reversed formula

 

[ACS_acoustics]

Just as a suggestion: (maybe for other future measurement situations)

This mic also has a rather lineair response. Not expensive: http://www.lineaudio.se/OM1.html
I can confirm that they are insanely matched / identical. In level and in frequency response. They not only measure but also sound great as omni.

If you already have an audio interface.... I would definitively go for a XLR mic. If you don't, then the benefit of USB is larger. If you choose for USB there is also a level calibration, that is nice. Level calibration is a 'thing' with just an XLR mic. Then you need extra stuff...

But if you have an audio interface... you could do measurements with multiple microphones. The program REW that most people use, now has the option for multiple mic's at the same time. Works really well. And with multiple input/outputs phase measurements are possible... that you just cannot do with just one usb mic. Meaning... you can go further... then 1x usb.

Another cheap microphone I found was the Mic W215, with some nice specs. I tried to purchase some, but there were some delivery issues... never got them. Now I don't need them any more.

I compared a few. I would personally stay away from the behringer mic.... The ones I saw... were too far of the other microphones.
If you've got the money... just go for earthworks. But that is a different price range

 

[JD1]

It's been some time but I guess I would revive it.

So I'm getting a focusrite gen3 2i2 for doing rew measurements for car audio, and I was looking at umik-2 but since I want to use the loopback from focusrite output to feed it to 2nd input and dsp at same time so I can use holmipulse for TA and phase alignment I need the focusrite anyway, so my question is:

Is beyerdynamic MM 1 (2023) which has calibration files for 0 and 90 degrees a superior choice to umik 2 since I'm already getting a audio interface or should I go cheap on xlr mic and use it just for TA and buy umik2 I'd prefer xlr + audio interface only but I'm not sure how beyerdynamic mm1 measures against umik 2, after this project I also want to do some home audio but that will have to come later so I wanted a good xlr mic so I wouldn't have to spend more in future , good as in sufficient but not low end.

Is beyerdynamic MM 1 (2023) a good buy and is it spl calibrated as well or is the 0 and 90 degree just for the angles?

Thanks for any feedback. Euroland btw.

I'd like to basically have a list like ASR does for products for xlr mics but I can't seem to find one nor the amps etc... in ASR except in the review threads.


Best regards

Ps: I have a cheap SPL meter just have no idea, yet, how I'd go about calibrating mm1 for spl everytime (if needed)

 

[Blumlein 88]

It's been some time but I guess I would revive it.

So I'm getting a focusrite gen3 2i2 for doing rew measurements for car audio, and I was looking at umik-2 but since I want to use the loopback from focusrite output to feed it to 2nd input and dsp at same time so I can use holmipulse for TA and phase alignment I need the focusrite anyway, so my question is:

Is beyerdynamic MM 1 (2023) which has calibration files for 0 and 90 degrees a superior choice to umik 2 since I'm already getting a audio interface or should I go cheap on xlr mic and use it just for TA and buy umik2 I'd prefer xlr + audio interface only but I'm not sure how beyerdynamic mm1 measures against umik 2, after this project I also want to do some home audio but that will have to come later so I wanted a good xlr mic so I wouldn't have to spend more in future , good as in sufficient but not low end.

Is beyerdynamic MM 1 (2023) a good buy and is it spl calibrated as well or is the 0 and 90 degree just for the angles?

Thanks for any feedback. Euroland btw.

I'd like to basically have a list like ASR does for products for xlr mics but I can't seem to find one nor the amps etc... in ASR except in the review threads.


Best regards

Ps: I have a cheap SPL meter just have no idea, yet, how I'd go about calibrating mm1 for spl everytime (if needed)

If you calibrate the MM-1 or other mic once you won't have to cal it everytime for SPL. A Umik usb mic is a convenience in that it is calibrated for SPL. If your SPL meter is fairly good calibrating with pink noise will likely work fine. You will be in the ballpark at least.

 

[JD1]

If you calibrate the MM-1 or other mic once you won't have to cal it everytime for SPL. A Umik usb mic is a convenience in that it is calibrated for SPL. If your SPL meter is fairly good calibrating with pink noise will likely work fine. You will be in the ballpark at least.

Thanks for the feedback, so mm1 is a better option in my case right?

 

[JD1]

I'm also considering buying a
Digital Sound 8930B to use for the SPL meter calibration in REW so then the MM1 would be spl calibrated correctly, correct?

 

[Blumlein 88]

These things are relative to what your intent is. The Beyer is a better mic than the Umik, but the Umik serves its purpose. Do you need spot on SPL calibration? Is within a couple db good enough. I'm not arguing for less good measurements, but acoustical measurements for most purposes aren't something you nail down within .1 db in use. Often as long as relative levels are known that is good enough.

But ultimately the Beyer is likely a better, more accurate microphone, and if you need to calibrate SPL levels then the better the calibration tool the better the result.

OTOH, I've sometimes used an interface and a good omni mic to adjust speakers in a room. I didn't have a cal file, just set the speakers by ear to something like 80 db, called it 80 dbSPL and did my measures. I didn't care within 5 db what it really was. I just need to make room adjustments with precision actually exact SPL wasn't a big consequence to my purposes. Obviously were I measuring speaker distortion such a cavalier approach is no good for sharing with others.

So yes, the 8930B is said to be accurate within +/- .4 db and should get you a good calibration which you can repeat/recheck with ease at 1000 hz.

 

[JD1]

Thanks alot for all the help, much appreciated.

I don't usually buy cheap as it tends to be more expensive, hence why I don't mind the extra 50€ for the spl calibrator. As opposed to buying Umik-2 I just wasn't sure the

Focurite 2i2 (3rd gen) + beyerdynamic mm1 + 8930B would be a superior choice against umik2 + focusrite+ cheap xlr + cheap spl meter.

I'm new to SQ and rew and all this stuff but I'm starting to enjoy the hobby albeit expensive as it is.

Thanks for touching speaker distortion since I actually am pretty interested about that, as I want as little of it as is possible, and since I'm new I prefer to spend a little more now (as long as it makes sense ) instead of regretting later with cheap stuff.


Best regards and an amazing 2025 to you.

 

[alpha67]

Hi everyone, I have seen this product recently and I am wondering if this could be used for the room calibration and speaker measurements?

https://www.daytonaudio.com/product/1974/imm-6c-idevice-usb-c-calibrated-microphone

A unique serialized calibration file is available for each iMM-6C. This calibration file can be used by most audio-analysis apps for Android, Apple, and Windows based devices that support microphone calibration.

The app they recommend is Audio Tools for Android and Apple iOS, it is for purchase:

https://play.google.com/store/apps/details?id=com.julian.apps.AudioTool

I am wondering if something like this would work with REW application on Windows?

 

[Blumlein 88]

Hi everyone, I have seen this product recently and I am wondering if this could be used for the room calibration and speaker measurements?

https://www.daytonaudio.com/product/1974/imm-6c-idevice-usb-c-calibrated-microphone

A unique serialized calibration file is available for each iMM-6C. This calibration file can be used by most audio-analysis apps for Android, Apple, and Windows based devices that support microphone calibration.

The app they recommend is Audio Tools for Android and Apple iOS, it is for purchase:

https://play.google.com/store/apps/details?id=com.julian.apps.AudioTool

I am wondering if something like this would work with REW application on Windows?

I had the same mic, the IMM 6 which had the TRRS plug. Yes, it will do a good job. I've checked it vs a Umik 1 and get the same results. I didn't know they had the USB C version. Might pick one up as a handy thing to take with you. I assume the built in ADC is good enough. If the specs are true it is.