Neumann k105 (km84 based) fits chinese body!

[kingkorg]

Well this is not what i expected! This thing fits Takstar cm60!!!

And it doesn't even matter what's behind it due to the capsule construction.

There are some quirks, so i'll explain.

The capsule has about 10db attention at 50hz. At the moment i don't see it as an issue because i can simply boost the low end to compensate with exactly same but opposite eq curve. There is also HF boost, I can address this the same way.

I previously thought this LF roll off could be because of the circuit of KMS105, but it seems not. My best guess without disassembling it is probably because of the very tight diaphragm. It takes 150db of spl, so this is probably the reason. But i could be wrong. There could be a cap inside.

What makes me excited is the exceptional off axis rejection, especially at 180°. And this is the exact thing i've been raving about, and how important the backplate construction is in kk84 type of capsule!

This capsule shows how Neumann addresses the resonances behind the capsule, and how important this part also is. Very tight rear air gaps!

I'm a bit hesitant to disassemble it, since it's sealed. But knowing myself i'll most probably do it eventually. Maybe I can finally come up with a solution for all those cheap capsules of this type.

 

[molke]

If that’s the measured capacitance in the last picture, 51 pF seems pretty high for a capsule of this size and construction?

What makes me excited is the exceptional off axis rejection, especially at 180°. And this is the exact thing i've been raving about, and how important the backplate construction is in kk84 type of capsule!

What was the distance for those off axis measurements? If it’s not too secret, I’d also be interested in window length.

 

[kingkorg]

If that’s the measured capacitance in the last picture, 51 pF seems pretty high for a capsule of this size and construction?

What was the distance for those off axis measurements? If it’s not too secret, I’d also be interested in window length.

Capacitance can indicate many things. If the diaphragm is tighter it can be moved closer to the backplate, and voila higher capacitance no matter the capsule size.

All are taken at 50cm outdoors 100ms window. I wouldn't take those off axis measurements too serious below 100hz.

 

[Icantthinkofaname]

Nice, I'd love to see that kind of construction on the aftermarket SDC capsules for cheap mics (like the things Mic-Parts and 3U sell).

 

[Icantthinkofaname]

So it's a super cardioid with great 180° rejection? Asking cause Neumann says the KMS105 as having "[a] tight supercardioid pattern without off-axis coloration".

 

[kingkorg]

Yes. However supercardioid should have some extra leakage from 180°, this one doesn't and my best guess is because of the plastic ring behind the capsule which physically prevents this from happening.

If you do this with a regular hyper and super capsules it creates all kinds of anomalies at 0°. By carefully tuning the slots on the side and "dose" the right amount of air (sound) to come through the slots you get this result. There is also not much space behind the capsule for it to create crazy resonances.

Sennheiser/Neumann does really remarkable work with newer models. I feel really bad people are so attached to vintage designs and don't seem to give them much credit for newer stuff. But i understand, if i just tested this capsule some years ago by just recording something i would discard it right off the bat. Weak low end, predictable high end boost = harsh, unusable.

Even knowing how this works, it would take insane amount of trial and error to mod an existing capsule to give me the same result. I don't even think i would ever get there. If i blindly copied the design and manufacured it, it would probably cost as much as the original.