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Old 8th November 2017, 07:32 PM   #11
wintermute is offline wintermute  Australia
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Measurement Mic. Diy Help
Out of those the second one looks the best. The third one I'd rule out completely.

The problem is knowing whether the posted FR curve is representative or not (ie what is the variability sample to sample). If it is then for any normal crossover work in the 300 - 5 Khz range I think it would be fine.

If they have good consistency you may even be able to make a generic calibration file from the posted response curve, however you would really want to try to compare against a measurement with a calibrated mic before trusting it. Of course if you have access to a calibrated mic you could make a proper calibration file

I think it would work fine with preamps designed for the panasonic mic's

Tony.
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Old 10th November 2017, 01:41 AM   #12
Ultima Thule is offline Ultima Thule  Europe
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Thanks Tony, I guess we have to order a bunch to get an average FR, any voluntaries?

Anyhow, when I searched the web for some month ago I came up with another measurement microphone which comes in a "ready" package, the mic is Superlux ECM999
Can be ordered from Thomann and other places for a bit under 40€
Superlux ECM999 - Thomann UK
Have seen these also on AliExpress but at no price advantage.

Seems like the Superlux microphones are originally from Taiwan.
http://www.superlux.com.tw/index.do

ECM999
Superlux - ECM999

Quote:
Sensitivity: -37dBV/Pa (14mV/Pa) 1Pa=94dB SPL (at 1,000 Hz Open Circuit Voltage)
Rated impedance :200Ω
Minimum load impedance: 3,000Ω (Obs! in the PDF it says min. 1kOhm)
Equivalent noise level: (A-weighted) 22dB
Max. SPL (1 kΩ load) :132dB SPL (THD≦1% 1kHz)
Dynamic range (1 kΩ Load) :106dB
Environmental conditions:
Polarity: Pin 2 output positive voltage (related to pin 3) when diaphragm receives positive pressure. (Diaphragm moving inward)
Connector: 3 pin male XLR type
Finish: solemn black finish
Weight: 150g (5.30 oz.)
Current consumption: 0.5mA
Noise ratio-to-Signal :70 dB
Power supply :9~52 V Phantom
Dimensions :Φ21.0x193.0mm (0.83x7,56n.)
Frequency Response :20~20000Hz
I noticed there's some discrepancies on the frequency response given in various PDF's for ECM999, see attached picture.

Another alternative could be ECM888B
Superlux ECM 888 B - Thomann Suomi
Superlux - ECM888B

Somewhere I saw a pretty good mic shootout test where the ECM-999 did quite well, at least for its price, have been surfing the net for a while to find the test again but I just can't find that link right now.
On the other hand, a lot could be saved buying an electret capsule for only couple of €$£ and save the money for a calibration, also the shipping cost for a tiny electret capsule is probably much cheaper, if it has to be shipped by post for calibration.
Attached Images
File Type: jpg ECM999 Frequency Response Discrepancies.JPG (97.3 KB, 150 views)

Last edited by Ultima Thule; 10th November 2017 at 01:46 AM.
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Old 13th November 2017, 02:04 PM   #13
Ultima Thule is offline Ultima Thule  Europe
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Some day ago skimmed through eBay for calibrated mic's, just thought I would attach some pictures of an "interesting" case, the asking price was ~700 US$, but as one can see from the calibration graph the mic (Type TL7405) has a 10dB droop from ~2kHz and above, ie. not much better than one of the electret capsule I found earlier, maybe this one has other qualities?
Attached Images
File Type: jpg TL7405 microphone calibration chart 01.jpg (242.8 KB, 139 views)
File Type: jpg TL7405 microphone calibration chart 02.jpg (215.7 KB, 138 views)
File Type: jpg TL7405 microphone calibration chart 03.jpg (216.9 KB, 137 views)
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Old 13th November 2017, 06:56 PM   #14
1audio is offline 1audio  United States
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Measurement Mic. Diy Help
The upper curve is the correct free field response (what you normally do for speakers). The calibration is using an electrostatic actuator which creates the equivalent of a pressure response. The difference is due to the physics of the size and shape of the capsule in free space. The mfr has a specific correction curve for the microphone diameter and the electrostatic coupler based on the physics.

Any microphone disturbs the sound field around it. The B&K mike book has a good description of the phenomena. https://www.bksv.com/media/doc/be1447.pdf Section 2 I think. Lots more than you may want to know.
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Old 13th November 2017, 07:02 PM   #15
1audio is offline 1audio  United States
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This info makes the mike specs suspect: Buyer be aware: AudioHipster AH-03 - Gearslutz Pro Audio Community even though the physics are correct. If the mike is not what they say it is that's a different issue.
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Old 6th January 2018, 07:07 PM   #16
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Quote:
Originally Posted by PRR View Post
Making a small f-l-a-t omni is not rocket science. They have become a commodity, like resistors. The design tends to a bass-droop and a top-ring. Some have more of both for better speech intelligibility. Others let the bass run below 50Hz, and mini-capsules tend to have enough damping to control (not eliminate) the top-ring.
Could you point me to a tutorial, please.

Quote:
Originally Posted by lholland View Post
Just FYI. I recently spoke to a guy deep into this part of the industry (a measurement mic mfg) and he said that the Panasonic mic element was the foundation of most low cost measurement mics on the market and that Panasonic's decision to end production was a huge hit to a lot of OEM's.

He also said that as of this time their isn't a replacement with the sample to sample consistency and reliability that the Panasonic unit had,
Thats sad. I began to look for calibrated mics but the ones that are recommended are in the range of 11K to 28K INR: too high for me because my sole reason at first for diyaudio was cost efficiency.


Quote:
Originally Posted by Ultima Thule View Post
I too have been looking long for a microphone suitable for my budget DIY stuff, had just a look at Mouser and checked through only a few, especially the brand CUI Inc. seemed to have a few new interesting microphones
please take a look at this too. After about a couple of hundred datasheet download I found this, its really cheap but almost very flat.

CMA-6542PF CUI | Mouser India

NB I am sorry for being very late till last I replied to this thread.
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Old 6th January 2018, 08:57 PM   #17
1audio is offline 1audio  United States
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The mike looks good. Decent SNR and supposedly extended bass is unusual. Consistency may be an issue. The sensitivity is listed at +/- 3 dB which is a lot. It means anything that works can ship. I don't think CUI makes them. They are sourced from China.

The best current vendor for mikes would be Primo with the Japanese obsession for quality. Still not all extended for HF or LF.
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Old 6th January 2018, 10:17 PM   #18
scott wurcer is online now scott wurcer  United States
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Quote:
Originally Posted by 1audio View Post

The best current vendor for mikes would be Primo with the Japanese obsession for quality. Still not all extended for HF or LF.
The Primo (?) small omni capsule sold as the Nakamichi CP-3 had an excellent HF response. The CP-1 and CP-2 were definitely Primo products. IIRC EM-21 and EM-23. The consistency is excellent still holding spec after 40yr.
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Last edited by scott wurcer; 6th January 2018 at 10:19 PM.
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Old 7th January 2018, 06:32 PM   #19
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What should I do? Which one should I get?
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Old 8th January 2018, 03:08 PM   #20
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Has no one found a way after the Panasonic WM61A got eol? What do you use guys, you buy branded calibrated mic or find one mic electret close to Panasonic WM61A and diy a mic?
I would also like to ask if there is a way to calibrate with software tools an uncalibrated mic electret?
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