I measured the deviation of 6 Earthworks microphones.

[SIY]

If you are an amateur and need a more accurate microphone, it should not be any of the Earthworks models

Because? I've used both (and several more) and found nothing "inaccurate" about mics like the M50 or M23R. These results look very much like what you get with B&K/DPA or PCB Piezotronics or GRAS.

 

[tjtz886]

因为？我同时使用了这两种（以及更多）并且发现 M50 或 M23R 等麦克风没有任何“不准确”的地方。

Please see the data sheet I give below. This is the pre-polarized 4189 model. Its original data is amazing. What is even more amazing is that it was used on the factory assembly line for 5 years. Then it came to me and I sent it to B&K laboratory for calibration. The data obtained was as perfect as it was when it left the factory.
This is not their best model. Those models with 200V polarized power supply can basically match the original data of the factory after 50 years.
The first model I came into contact with was the 4133, which requires a 200V power supply. I bought it from Europe and sent it to B&K laboratory for calibration. What is incredible is that it is basically consistent with the original data of the factory. This microphone was produced in 1976.
Later, I got the answer from some professionals that when measuring microphones, B&K is the first tier. No brand can compare with it, including similar products such as GRAS and PCB.

 

[tjtz886]

Since then, I have left other brands and now have the three specifications of 4189/4191/4939.
4939, it can go to 100K, and the original data is available.
For audio measurement, there is no need to import calibration data.

 

[SIY]

Later, I got the answer from some professionals that when measuring microphones, B&K is the first tier. No brand can compare with it, including similar products such as GRAS and PCB

Having used and owned all of them, that has absolutely not been my experience. They all have their own advantages and disadvantages, but they all work superbly for acoustic measurement.

Note that the calibrations you attached are NOT acoustic, they're actuator. This is an extremely important distinction if you're trying to make comparisons.

 

[tjtz886]

Having used and owned all of them, that has absolutely not been my experience. They all have their own advantages and disadvantages, but they all work superbly for acoustic measurement.

Note that the calibrations you attached are NOT acoustic, they're actuator. This is an extremely important distinction if you're trying to make comparisons.

Yes, they are both reference grade in the amateur user range. But in terms of time stability, B&K is truly in a class of its own.

 

[SIY]

Yes, they are both reference grade in the amateur user range. But in terms of time stability, B&K is truly in a class of its own.

I have not seen any of them significantly drift out of calibration, though admittedly I've only had the PCBs for 8 years and the Earthworks for 5. Do you have data to the contrary?

 

[tjtz886]

I have not seen any of them significantly drift out of calibration, though admittedly I've only had the PCBs for 8 years and the Earthworks for 5. Do you have data to the contrary?

I have used M30, which has deviated from the so-called standard (±1dB -3dB), and the 20k frequency position is about +2.5dB. A professional told me that it uses a plastic diaphragm instead of a laboratory-grade stainless steel diaphragm.
Of course, my answer just now is only based on second-hand products. The new B&K is much more expensive..... In some ways, these two brands will basically not be chosen together.

 

[SIY]

A professional told me that it uses a plastic diaphragm

It does, metallized polyester. Which means you can't compare the acoustic calibration needed for that material to an actuator calibration (which is a shortcut method for metal diaphragms).

I don't have the M30 any more, but the M23R I do have is absolutely dead-nuts on calibration after 5 years.

 

[morillon]

It does, metallized polyester. Which means you can't compare the acoustic calibration needed for that material to an actuator calibration (which is a shortcut method for metal diaphragms).

I don't have the M30 any more, but the M23R I do have is absolutely dead-nuts on calibration after 5 years.

for a language barrier story...I don't understand what you mean...
the 5 year old m23r is no longer consistent with its original curve?
thank you
;-)

 

[SIY]

the 5 year old m23r is no longer consistent with its original curve?

Exactly the opposite- it still conforms perfectly.

 

[morillon]

Exactly the opposite- it still conforms perfectly.

thanks.. ;-)

(for info if interested, earthworks just told me that they had a control-recalibration package for 162 dollars)

 

[morillon]

Exactly the opposite- it still conforms perfectly.

ps if you have the means, the opportunity, the need, to have your m23r checked again, new cal files, I would be curious to observe the aging. I don't have the personal justification for it at the moment (especially I'm not American)..
but I'm curious
;-)
(but I may have the opportunity to make a modest observation regarding a bk used in certification and very controlled...maybe it will be relevant in 1k/23khz)