Flat response handheld condenser

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kingkorg

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Apr 15, 2017
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So, i wanted to make a flat response handheld condenser since forever.

The capsule sourcing was an issue, they are rare and expensive in cardioid variant.

And then i bought Line Audio CM4. I was sceptical at first because of the price, until i tested and measured the thing. It is truly a ruler flat cardioid! At least in my testing conditions, and since Line Audio claims that as well, I consider it to be flat.

So i took it apart, in order to find out what it's about, and make my own version. In the end i gave up, it has rather complex circuitry with some advanced filtering (i hadn't seen in a mic before),  and it has a phisically modded capsule which costs about 50$ stock.

So it simply can not be made as a DIY, at this price, and dimensions. It uses SMD.

So i took another road. I decided to put the whole thing, since it's tiny in a Neumann KMS105 chinese knockoff. I removed it's internals, which were not impressive, and whole CM4 fitted inside. It works remarkably well.

Maybe someone gets inspired by this. The great thing is, you just unscrew the XLR screw, and remove CM4 when you want to use it on it's own.

Here is the self explanatory XLR adapter:
 

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Goes into the mic. The joint between male and female part of the adapter is glued with epoxy, the top of the female part of the adapter which is glued to the male XLR is rubbery, so it provides shock absorption for the CM4 on the inside, so the mic is virtually floating once put inside host body. 
 

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So you just slide it in, tighten the screw of the XLR, not seen on this image sadly, but we know where it sits.
 

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This chinese kms105 comes with this rubber ring which provides additional shock absorption.  The white ring between black one and CM4 is the one i made out of some kitchen rubber band.
 

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And the final product. The KMS body is beautifully made btw.

I experimented with some foam inside the grille to get best plosive protection.

The headgrille and foam did slightly impact the response above 10k, but variation compared to stock is +-1db. So it's still a flatest cardioid i've ever had.
 

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Is that the MADON KMS105 knockoff? Is the stock version of it as horrible as I'd assume? There's no way a $60 counterfeit of a Neumann can be any good in my eyes. Asking not because I'm interested but more curious, since they also have the guts to charge something line $750 for a counterfeit U87ai. If they are any good, I don't know why they don't just make it look a little different and not try to pass it off as a Neumann. They're not fooling anyone.

More on the topic of the actual project, do you find the CM4's capsule to have too wide of a cardioid pattern? I've heard it's pretty wide, approaching omni territory. I've been considering grabbing the CM4 and OM2 or whatever the omni is called, as well as their 8 channel preamp. I'm amazed at how there are all these amazing cheap mics (and even some more costly boutique mics) in Europe (and Oceania I guess, Beesneez has a nice sounding affordable CK12 and some good sounding mics) and then in North America we have bad clones that cost $500-$1000 that just sound like Chinese mics costing a fraction of the price (just about every C414 and C12 clone I can think of).

This seems like a great way to avoid the issue of stage/handheld condensers generally having lower sensitivity.
 
It is a Madon. The body alone is worth the price imho. The circuit is tiny smd bm800 variant, so it is useable, but with a better capsule than stock. Stock capsule is way too bright, and lacking bass big time. It can be EQed, but not quite useable.

CM4 is slightly sub cardioid in the mids, no where near omni, i think the guy at Line Audio is just being too honest about his measurements. It is as cardioid as any cardioid i have. CM3 was more towards omni, this one is more directional.

If there is a desert island mic for me it has to be CM4. I have a feeling they are not making tons of money on this one, i think they are there just to make name for the company.

Having in mind the price of the labour in SE, to develop unique circuit, produce enclosure, pcb, and use quite pricey capsule, modify it HEAVILY by hand to the point it almost has nothing in common with the original i'd say this mic can cost 500$ easily! It is true boutique mic, all made in Sweden, capsule made in Japan.

It's quiet, it is flat, sounds like a dream. Only downside i can think of is it's pretty sensitive to plosives and wind noise. But it's expected as it has huge low end and goes quite low. Not an issue with a regular pop filter.
 
A Neumann KMS 105 for example, has a sensitivity of (only) 4,5 mV/Pa.
Thats is a lot lower than most condenser microphones, just a little more than a dynamic microphone.
I suppose this is done intentionally, because these microphone are usually used very close to the sound source.
(And thus receive a high SPL.)
 
RuudNL said:
A Neumann KMS 105 for example, has a sensitivity of (only) 4,5 mV/Pa.
Thats is a lot lower than most condenser microphones, just a little more than a dynamic microphone.
I suppose this is done intentionally, because these microphone are usually used very close to the sound source.
(And thus receive a high SPL.)
Agreed, that's why I wouldn't call it an "issue", but rather a well thought-out decision.
 
I think there's a psychological element to it as well. I know a lot of singers who freak out if they see gain level turned down on a mixer. They are used to high amounts of gain used with dynamics, and feel they have somehow less power if the gain is turned down.
 
kingkorg said:
I think there's a psychological element to it as well. I know a lot of singers who freak out if they see gain level turned down on a mixer. They are used to high amounts of gain used with dynamics, and feel they have somehow less power if the gain is turned down.
Conversely, they would think the mic is no good if they have to crank gain.
Making mics implies a lot of psychiatry.
 
Did you consider to add the original Neumann internal popshield?
They are not very expensive and seem to work.
The capsules of the KMS104/105 are also pretty sensitive to plosives, without the extra popshield.

https://sennprospares.co.uk/neumann/neumann-kk104-kk105-capsule-spare-parts/sennheiser-kms-104-internal-popshield-for-the-mesh-grill-510304.html
 

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