Hi all,

Over 20 years ago, Linkwitz introduced to the DIY community the WM61a mic capsule as an ideal unit with which to make a remote powered (9V Batt) measurement mic that could be used to measure loudspeakers. Shortly thereafter, Panasonic stopped making them. There are now several Chinese capsules being sold as "replacements" for the WM61A. Word on the web is that they are not a good replacement.

So I ask, does anyone have a great replacement for the WM61A that is commonly available today in the US?

I have included some WM61A data sheets and a commonly used preamp.

 

If You are not an actual "Speaker-Design-Engineer" who is
designing new Drivers, it really doesn't matter that much what Mic You use.

But, being able to note changes in Speaker-Response is certainly useful.

Here is a pretty reasonable replacement from DigiKey ......... 668-1391-ND
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If You are not an actual "Speaker-Design-Engineer" who is
designing new Drivers, it really doesn't matter that much what Mic You use.

But, being able to note changes in Speaker-Response is certainly useful.

Here is a pretty reasonable replacement from DigiKey ......... 668-1391-ND
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.
.

If the datasheet is to be believed then the DigiKey one has a better signal-to-noise than the original, but a rather less flat response in the 10kHz region.
However, neither quotes the sound level at which the SNR was measured nor the weighting factor applied.
A studio condensor mic will manage about 76dB, 13dB better.

This thread appears to be a continuation of this one:
https://forum.allaboutcircuits.com/threads/beau-schwab-electret-mic-preamp.199437/

My final circuit in post #20 (with the op-amp) is about as good as you can get, considering the limitations of the microphone.

MEMS microphone have a slightly better SNR, but much better reliability as the JFET lead doesn't come detached from the element due to poor crimping.
https://invensense.tdk.com/wp-content/uploads/2016/02/DS-000044-ICS-40618-v1.0.pdf?ref_disty=digikey
The output is buffered so is less difficult to amplify.

 

There's the Behringer ECM-8000, which is comparatively cheap for a measurement mic. I suspect the calibration mics supplied with many AV receivers aren't awful; those turn up at thrift stores from time to time.

 

@oneoldude42BallSportsGear Over 20 years ago, Linkwitz introduced to the DIY community the WM61a mic capsule as an ideal unit with which to make a remote powered (9V Batt) measurement mic that could be used to measure loudspeakers. Shortly thereafter, Panasonic stopped making them. There are now several Chinese capsules being sold as "replacements" for the WM61A. Word on the web is that they are not a good replacement.

So I ask, does anyone have a great replacement for the WM61A that is commonly available today in the US?
Over two decades ago, Linkwitz introduced the WM61a mic capsule as an excellent choice for creating a remote-powered (9V Batt) measurement microphone for loudspeaker analysis in the DIY community. Unfortunately, Panasonic ceased production of the WM61A, and there are concerns about the quality of some Chinese capsules marketed as replacements. Currently, there's a search for a reliable alternative commonly available in the US. If anyone has found a suitable replacement for the WM61A microphone capsule, your insights or recommendations would be greatly appreciated.

 

Capsule mics like that are going out of fashion rapidly. When was the last time you saw one in a mobile phone handset?
They are no longer in landline phone handsets as the alternatives developed for mobile phones get cheaper.
What else would they be needed for?

 

"" ............. does anyone have a great replacement for the WM61A ......... ""
It depends on what You want.
This is a rather vague question.

Do You intend to try to duplicate the Physical and Electrical modifications outlined
in the ancient article ( which I also have ) by Linkwitz ?????
If this is so, I'd say you're looking for unobtainium.

I'd say that your best bet would be to go with the Beringer-Calibrated-Mic mentioned above.

Besides, there are many factors that are far more important than Frequency-Response in a Sound-System.
First, and most important, is the treatment of the Room that the system will be installed in,
Second is the Transient-Response,
Third is Ringing and Driver-Breakup characteristics,

And, at the bottom of the pile ........ Frequency-Response is what ~27-Band-Graphic-EQs were invented for.

A Ported-Cabinet will never produce High-Fidelity-Bass,
although it "might" have some serious "Low-Frequency-Content".
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I also mourn the downward availability of Electret mics.

Electret microphones are following the dynamic microphones, which followed the crystal piezo microphones, down the semi-extinction path.

For the simple reason that MEMS microphones can now be manufactured very cheaply at semiconductor fabs, which also allows a total integration with an amplifier, signal conditioning and even A/D conversion.
All within a miniature SMD package.

I don’t think that Electrets will become completely obsolete, only that the high performance, inexpensive, consumer-grade devices will.

 

Hello,

Do you want to perform SPL measurements?
Then have a look at fig 8 of the attached page:
https://sound-au.com/project93.htm
It shows the modification of a panasonic electret mic.

Bertus