Cheapest "reference" option - Cross Spectrum Labs calibrated umik1 or 2, then use REW or similar to make a cal file for whatever XLR mic you can find. Sometimes cross spectrum sell calibrated cheap XLR mics.
Mid - Audix TM1 or MicW M215, EMX 7150 (although that seems like a sound tech show mic, massive SPLs)
High - earthworks anything
God tier - B&K , probably beyond the requirements of anyone on this forum.
Mine still in transit
Mid - Audix TM1 or MicW M215, EMX 7150 (although that seems like a sound tech show mic, massive SPLs)
High - earthworks anything
God tier - B&K , probably beyond the requirements of anyone on this forum.
Mine still in transit
Thanks
But the only driver really being able to do that in my lab where 2 M74A in parallel.
A half serious measurement room/chamber should have lower noise floor as 20dB(A)Spl! Not so easy in urban environment but at my place ... I never could measure my noise floor but I can perfectly measure the noise floor of my lowest noise mic (TLM193 - <10dB(A)Spl).
When you have a noisefloor >10dB(A)Spl don't even think about measuring 0,01% THD ...
So let's finish with some bragging ...
These M215 are proper Class1 capsules with 48V phantom power electronics. They are still 1/2" but behave up to 20kHz and come with individual calibration - it's a bargain for the price.
Earthworks M50 is probably overkill for measurements up to 20k but it behaves perfect in this range, I don't need a calibration file which is convenient. Type in the sensitivity and you are good to go. For normal use a M30 is probably good enough and also behaves up to 20kHz. Not sure if they are really higher quality as an M215 ... noise is higher, for sure quality control is better and the smaller capsule has benefits at very high frequencies. But I would guess the M215 capsule is easy as robust in long term as an Earthworks capsule.
Earthworks M50 is probably overkill for measurements up to 20k but it behaves perfect in this range, I don't need a calibration file which is convenient. Type in the sensitivity and you are good to go. For normal use a M30 is probably good enough and also behaves up to 20kHz. Not sure if they are really higher quality as an M215 ... noise is higher, for sure quality control is better and the smaller capsule has benefits at very high frequencies. But I would guess the M215 capsule is easy as robust in long term as an Earthworks capsule.
Does anyone have knowledge of how microphones assigned calibration files?
When I first purchased my Xref20 in mid 2020, calibration file was available to download online. Just supply the serial number.
Recently I discovered that Sonarworks offers calibration files for 30 degree and 90 degrees.
Great, I’ll buy another one for multichannel room EQ.
I just supply the serial number for the microphone. Much to my surprise, even using the serial number of old xref20 v4 that I bought years ago, well I could download these "new" 30 degree and 90 degree calibration files from the from website.
So if this is a calibration file is made available made POST sales/delivery., I wonder how they make them?
When I first purchased my Xref20 in mid 2020, calibration file was available to download online. Just supply the serial number.
Recently I discovered that Sonarworks offers calibration files for 30 degree and 90 degrees.
Great, I’ll buy another one for multichannel room EQ.
I just supply the serial number for the microphone. Much to my surprise, even using the serial number of old xref20 v4 that I bought years ago, well I could download these "new" 30 degree and 90 degree calibration files from the from website.
So if this is a calibration file is made available made POST sales/delivery., I wonder how they make them?
The polar response of the electret capsules is very predictable and consistent. This makes it possible for manufacturers to provide generic calibration files for those angles based on the on axis calibration. Effectively it is an inverse filter for the effects of the capsule being off axis.
It is not the same thing as a true calibration at those angles. Most uses for 90 degree orientation is for in room measurements where ultimate precision isn't so important.
You can make your own 90 degree calibration file. I've used this method before and it works.
https://johnr.hifizine.com/2014/09/how-to-make-a-90-degree-calibration-file/
It is not the same thing as a true calibration at those angles. Most uses for 90 degree orientation is for in room measurements where ultimate precision isn't so important.
You can make your own 90 degree calibration file. I've used this method before and it works.
https://johnr.hifizine.com/2014/09/how-to-make-a-90-degree-calibration-file/
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The higher you push the output at 3% (or 1% here) THD the less mic. distortion will be present with near-field (lower freq.) distortion testing, though as others have mentioned 1/2” mic.s with low distortion don’t have really low distortion when compared to low distortion larger mic.s.
This is because as you get closer to the source (driver under test) the Spl increases dramatically - so near-field testing can get really loud for the mic. depending on just how close the mic. is to the source.
Note though that I’m not sure it’s a different mic., the website only lists the M215. ..Perhaps the 215 has a “do not exceed Spl of 145db”, but the 1%THD rating is at 135db???
Regardless, that $379 US is a lot of mic. for not a lot of money; even when it was near $500 it was a good deal.
This is because as you get closer to the source (driver under test) the Spl increases dramatically - so near-field testing can get really loud for the mic. depending on just how close the mic. is to the source.
Note though that I’m not sure it’s a different mic., the website only lists the M215. ..Perhaps the 215 has a “do not exceed Spl of 145db”, but the 1%THD rating is at 135db???
Regardless, that $379 US is a lot of mic. for not a lot of money; even when it was near $500 it was a good deal.
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Yes, that was one of the selling points for me that the preamp can be completely bypassed.
It takes higher SPL. Which is achieved with lower sensitivity of the capsule. Nois of the amplifier stays the same -> self noise rises.
Which means it's worse for THD measurements and measurements at 1m/1W but takes higher SPL levels for near field measurements.
Nearfield is normally in the range of 20dB higher as 1m far field (depends on membrane size). So with 135dBSpl max (at which THD level?) you can measure the equivalent of about 115dBSpl in 1m. So your normal measurements up to 105dBSpl are save, even in nearfield.
I'm pretty sure these microphones are made by BSWA, my capsules say MP309 but I can't find information about these.
And the mic costs €500,- in Europe ...
I don't understand this statement... what is the "preamp section"? is this part of the USB audio interface, or something else?
The microphone pre amplifier section of the interface. In a lot of interfaces the signal has to go through the pre amplifier section whether it is mic or line level. Most preamps in interfaces have a gain dependent frequency response or are otherwise the least transparent part of the device.
On the ID24 it has an insert loop that allows the pre amplifier section to be bypassed and go straight into the A/D converter. That also means the source needs gain control.
On the ID24 it has an insert loop that allows the pre amplifier section to be bypassed and go straight into the A/D converter. That also means the source needs gain control.
The case for stepping up from a microphone that costs more than a tank of fuel...
https://www.mtg-designs.com/tips-tricks-tests/measurement-mic-tests
In other news... new high SPL mic from iSEMcon coming...
CPX-1212
1/2 capsule:
Class 1 IEC 61672
XLR Phantom powered 12-48V
@48V max SPL 154dB
€1250
https://www.mtg-designs.com/tips-tricks-tests/measurement-mic-tests
In other news... new high SPL mic from iSEMcon coming...
CPX-1212
1/2 capsule:
Class 1 IEC 61672
XLR Phantom powered 12-48V
@48V max SPL 154dB
€1250
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Holy moly....
Sadly a bit too expensive for me. The 140 dB of my iSEMcon EMX-7150 have to be enough....
Well, that one is in the same league as the M2215 from NTI. Good that that one gets some competition.
Using the class 1 type 2 high-Spl capsule 160db:
https://www.akulap.de/joomla/index.php/en/en-shop/product/view/17/11
https://www.akulap.de/joomla/index.php/en/en-shop/product/view/17/11
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It is quite typical to have <10dBA with closed windows and fridge&fan off late at night (after 8 pm) or early morning on weekends, even in condo urban settings. Home theater rooms - easy.
I would prefer a B&K but $$$... I use a dual-mic setup instead. A primitive ECM8000 (34 dBA, 105 dB at 10%) and AT4040 with 12 dBA self-noise and 145 dB at 1% THD (shall have 0.01% at 125). Dynamic range is limited by the amp noise at ~100 dB. Of course, ECM8000 is used only to calibrate the condenser.
PS> I love your mics