New 22mm (km184/kk105 style) Capsule

[pmfalcman]

However i am not sure if the issue was in the lack of air volume, or if the edges were creating internal reflections.

Thanks, I see what you mean.

But I couldn't help but notice that new slots have quite jarred edges. Wouldn't it introduce micro-reflections/diffractions?
I guess the speed of the air is too low to consider effects of turbulent flow (diminishing effective opening).
I'm not savvy enough to know at which point "bad" edge starts to matter acoustically.

 

[kingkorg]

But I couldn't help but notice that new slots have quite jarred edges. Wouldn't it introduce micro-reflections/diffractions?

You need to take sound wavelength into the account.

 

[Paul W]

Is there anything tricky about disassembling and reassembling these before/after modding the slots?

 

[kingkorg]

Yes, unfortunately. Trickiest part is to make sure the tightening ring is not over tightened (this wrinkles the diaphragm), and there are no debris between the diaphragm and the backplate. This is tricky as the diaphragm can't be seen properly under the front grille/plate. I have done reassembly several times without the grille/plate in order to make sure everything looks nice. I eventually assembled everything once I was certain no dust was trapped under. Measurements also confirm all is good. This is particularly challenging with stock spacer because it is so slim. Also important to remember how the holes between the metal and plastic transparent backplate are NOT ALIGNED!

In theory the slots can be drilled through or filed without disassembly, but you have to make sure no debris is left behind.

 

[pmfalcman]

You need to take sound wavelength into the account.

OK, I got it.
I was thinking of terms of airflow not sound wavelenghts

 

[pmfalcman]

One of my capsules developped a hum. It wasn't there and then it was. It wasn't dropped, dessicating packs didn't help, so not a question of humidity.
Constant white noise. So it prompted me to disassemble it and perform Kingkorg Mod, thinking: it's probably gone anyway, I can experiment freely. If it dies, it dies but I will learn something (never disassembled a capsule before, all these microns inside creep me up a bit).
Couldn't find my file so I drilled it. Put together and it lives. The hum is gone.
Sooo... I modded the second one. It survived as well.

One has easily visible spacer (red), the other one has probably a transparent spacer (would it work without one?). All I could see was a glistening ring. No, I wasn't brave enough to touch it.

Right from the start they had different sensibilities. Quite pronounced difference in levels. After swithing bodies (CM-60) the difference diminished significantly but is still there. This didn't change after the mod.

 

[pmfalcman]

I got tired of the unevenly drilled holes so I set to make nice, even vents.
They came out at 2 mm wide.
And the RF sensibility went wild.
Huge peak at 50 Hz plus beutiful harmonics and very audible hum.
Unmodified capsule has a peak at 50 Hz too but it's not very pronouced nor audible.
Original Takstar capsule - no peak.

Outdoors it diminishes obviously but indoors is really impressive.

Is there a way to remedy this, other than wrapping the capsule in fine mesh?
Or building a huge Faraday contraption?

 

[pmfalcman]

Blue unmodded. Equal gain for both mics.

 

[kingkorg]

I got tired of the unevenly drilled holes so I set to make nice, even vents.
They came out at 2 mm wide.
And the RF sensibility went wild.
Huge peak at 50 Hz plus beutiful harmonics and very audible hum.
Unmodified capsule has a peak at 50 Hz too but it's not very pronouced nor audible.
Original Takstar capsule - no peak.

Outdoors it diminishes obviously but indoors is really impressive.

Is there a way to remedy this, other than wrapping the capsule in fine mesh?
Or building a huge Faraday contraption?

Add fine mesh on the inside and cover the slots?

 

[pmfalcman]

Add fine mesh on the inside and cover the slots?

Inside...
You have great trust in my skills. Thank you.

I do smell a whiff of a challenge in the air.

 

[ccaudle]

Add fine mesh on the inside

What metal is the capsule housing made from (or plated with if the surface is different than interior)? I was just wondering if solder would secure the mesh, or if you would need a mechanical attachment to make sure the mesh contacted the housing firmly enough to ensure electrical contact without oxidation between the mating surfaces.

 

[kingkorg]

What metal is the capsule housing made from (or plated with if the surface is different than interior)? I was just wondering if solder would secure the mesh, or if you would need a mechanical attachment to make sure the mesh contacted the housing firmly enough to ensure electrical contact without oxidation between the mating surfaces.

Off the top of my head, from memory, i'd say it's all brass. But can't say for sure, don't have the capsule with me.

 

[pmfalcman]

It's solid brass.

Though the mesh can be soldered on the exterior only.
Internal mesh has to be inserted together with the whole package: front mesh, grille, membrane, backplate and rear plate, placed in narrow space between backplate and rear plate. I draw this info from memory i.e. from nothing.
As far as I remember (i.e. not far) the rear plate and backplate are fixed together (brass screw) and and slide out as one assembly.

You'd need to have the casing machined inside to create a recession in which the mesh could hide.

 

[jp8]

Looks like this capsule is used in a KMS105 clone from Aliexpress:

https://a.aliexpress.com/_EQS3uHt

They call it High Quality.... My son has another KMS105 clone, but that one has a different capsule and is for sure not a supercardiod. Sound isn't bad, but it's very sensitive to plosives and feedback. Even adding a foam in the capsule did not solve the plosives issue. The fine mesh grille inside isn't as fine as from a real KMS105.

Assuming the "High Quality" KMS105 clone does indeed have the capsule as discussed here in this thread, I'm tempted to buy such a KMS105 clone out of curiousity. Or did anyone already try one?

Jan

 

[kingkorg]

Looks like this capsule is used in a KMS105 clone from Aliexpress:

https://a.aliexpress.com/_EQS3uHt

They call it High Quality.... My son has another KMS105 clone, but that one has a different capsule and is for sure not a supercardiod. Sound isn't bad, but it's very sensitive to plosives and feedback. Even adding a foam in the capsule did not solve the plosives issue. The fine mesh grille inside isn't as fine as from a real KMS105.

Assuming the "High Quality" KMS105 clone does indeed have the capsule as discussed here in this thread, I'm tempted to buy such a KMS105 clone out of curiousity. Or did anyone already try one?

Jan

Actually the original KMS105 has also issue with plosives, but probably not as bad.

What i did with my clone is make a hole in smaller inner mesh, and i squeezed foam through it so it fills the whole area between outer and inner grille.

Also i have some foam on top of the capsule.

 

[pmfalcman]

Soooo... Several points here:
@kingkorg should have his descripiton officially changed from "well-known member" to "sadistic golden-tongued devil".
Thank you, @kingkorg.
I thought of putting the mesh inside but rejected this idea and tried to forget about such masochistic exercises. You made me think "or maybe I'll try?"
So I tried. In 30+ °C. No A/C.
It's doable.

All one needs is to cut a 2,5 mm wide (max!) strip of brass mesh, cut it to length, unscrew the capsule's retaining ring, lift (with tweezers!) the plastic (teflon?) back plate, place the strip inside, put back the back plate and screw in retaining ring.
Easy-peasy.
Confirmed - no soldering possible. Without using very fine mesh and machining the capsule's body inside, that is.





50 Hz hum is gone.
Bottom end is a bit better, I think. More sophisticated equipment than mine needed.
Mesh reduced the air flow for sure but the slits cannot be opened more. Still, the RF or rather AC 50 Hz rejection is better than in unmodified capsule.


(Sound source: strong gust of wind in trees, mics inside the house)

 

[kingkorg]

Soooo... Several points here:
@kingkorg should have his descripiton officially changed from "well-known member" to "sadistic golden-tongued devil".
Thank you, @kingkorg.
I thought of putting the mesh inside but rejected this idea and tried to forget about such masochistic exercises. You made me think "or maybe I'll try?"
So I tried. In 30+ °C. No A/C.
It's doable.
View attachment 131585
All one needs is to cut a 2,5 mm wide (max!) strip of brass mesh, cut it to length, unscrew the capsule's retaining ring, lift (with tweezers!) the plastic (teflon?) back plate, place the strip inside, put back the back plate and screw in retaining ring.
Easy-peasy.
Confirmed - no soldering possible. Without using very fine mesh and machining the capsule's body inside, that is.

View attachment 131586

View attachment 131587

50 Hz hum is gone.
Bottom end is a bit better, I think. More sophisticated equipment than mine needed.
Mesh reduced the air flow for sure but the slits cannot be opened more. Still, the RF or rather AC 50 Hz rejection is better than in unmodified capsule.

View attachment 131588
(Sound source: strong gust of wind in trees, mics inside the house)

Awesome man!

 

[pmfalcman]

Thank you
Hope this can help someone.

Bit more technical details:
The brass mesh I used is 0,3 mm wire thickness with 0,5 mm spacing.

On one hand it may be a bit thick but it doesn't deform easily and has nice spring to it which helps maintaining good contact with the outer shell.

 

[jp8]

Out of curiousity, I bought a KMS105 with the 22mm capsule. Extremely noisy and still sensitive to plosives, though less so compared to the KMS105 clone with electret capsule. With some additional foam and better head amp design with lower noise, this could make a usable handheld mic. A future project.

On the left, the electret clone, on the right the KMS105 with the 22mm capsule. If you want to order it from Aliexpress, then watch the pictures so you get the one with 22mm capsule. The ads call it the "high quality version".

Jan