Making a LDC Capsule - Videos

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kingkorg

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That one seems to be based around this Neumann's omni capsule. If so you need to have only center part metalized, and clear ring around it. Otherwise the capacitance will be way too high.
 

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Murdock

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Hmm the capsule thats still good has the whole diaphragm metalized. I‘ll attach a picture later. Capacitance of that capsule is under 50pF if my memory serves me well.
 

Tim Campbell

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Yes from my exprience they are the same as am M7 capsule. some have the gold on the inside towards the backplate and make contact by a carbon button.
 

RJ

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Great stuff RJ, congratulations

How have you done the diaphragms? which materials did you use?

I glued 5um aluminium coated mylar to some used copper seals I had lying around at work. Then carefully pressed them on top of my ring which I had also applied supperglue before. No fancy tensioning rig at all. I just tried to tension the membrane enough to get rid of all the wrinkles. Then I cut off the membrane around the ring and bolted it to my back plate using nylon bolts. With some plastic foil as spacer. I guess the tension is a little bit higher than I would have hoped it to be. At least I guess it is, since my sensitivity is lower than expected. By the way, my back plate is quite rough. Right of the lathe without any polishing. Seems to work just fine. And I did not have to use the clean room either :p Thanks for all the good material!
 

Tim Campbell

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Some backplates are rough, but flat which is fine as long as your membrane never hits it. The edge of every hole is a potential razor. Try turning up the polarization voltage.
 

Tim Campbell

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Thanks Tim!
One last question.
I just checked the capsule and it seems the backplate portrudes over the tension ring. So I would need an isolator, right? Would I have to place a clear mylar film under the diaphragm in the tension Ring to isolate the diaphragm from the backplate and act as the spacer at the same Time?
But then the diaphragm could not move because it would be stretched over the backplate right?
Are you sre there isn't a way of adjusting the backplate distance with some of those screws? perhaps the one in the center of the backplate or those springs? The backplate looks insulated which would mean the membrane is ground.
 
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Murdock

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Are you sre there isn't a way of adjusting the backplate distance with some of those screws? perhaps the one in the center of the backplate or those springs? The backplate looks insulated which would mean the membrane is ground.
I will check. Either I can't see the distance or there is something else going on because on the good capsule I can clearly see, that the membrane is stretched over the edge of the ring that surrounds the backplate.
Yes, you're right. The membrane is connected to the housing.

image00002.jpeg
 

kingkorg

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Not a video, but i wanted to re-share these images of Blue's marvelous approach to modding and tuning k67 capsules. My guess is they use existing k67's and add this tuning disc as a rear backplate to tune the response and polar pattern. So dear people with machining skills here's a simple way to do a killer mod for readily available capsules.
 

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Tim Campbell

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This way of turning a multipattern capsule into cardioid only with one membrane though they can sound ok they usually cause a lot of strange peaks in the low end. Been there, done that.

I wish David Bock still contributed here. He has done a lot of research in this area.
 

GeorgeToledo

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Some people do not suffer fools gladly.

There are better things to do in a day than argue with people over patently absurd statements or to patiently teach people what they don’t understand, probably while also being insulted.
 

GeorgeToledo

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Tim, do you know of any published materials you could share or point to, concerning priming mylar with other metals prior to gold evaporation?
 

GeorgeToledo

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It now comes to mind - in context of backplate manipulation and I am guessing part of what Tim may be referring to in thinking about David after the post about the Blue capsule; people don’t seem to generally know that the K67 capsules in those Soundelux mics are not strict K67 clones, they were purposely designed for different off axis pickup. I’d guess Bock has maintained this through the years.
 

dima_k85

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Everyone who has belonged to this forum for the last 18 years knows that I bought every roll of AKG nos stock membrane material before I even started my CK12 production.
Again, just words. I asked about the proofs that "The bond I acheive is certainly better than AKG's". You don't have them, admit it.
Moreover, it is not correct to compare material from 18 years ago.
You obviously know nothing about membranes
Are there proofs? Again, just your imagination.
 

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