aluminum vs. gold vs. nickel vs. brass plated caps...
« on: January 10, 2005, 10:22:58 AM »
allright. if i remember the neu*mann m50 (the popular deca tree mic) is an aluminum cap, all the popular new mics are gold, neu*mann km 254/256 is nickel, original c12 is brass.

how  much difference in the sound of the mic is coming from the actual material compared to grill, cap hole size and spacing, mylar thickness, ect?

and when you send these original caps back to the manufactuer, do they put gold back on or do they reskin them with original materials?

is one easier to apply or cheaper? whats the use of using different metal substances?

...has a 'gold sputtered capsule for vintage sound'...


aluminum vs. gold vs. nickel vs. brass plated caps...
« Reply #1 on: January 10, 2005, 10:43:13 AM »
The first M50 was Al then there were PET, Ni and now Ti,  IIRC from the charts at the neumann site.

You have yor mass and your thickness The Ni is about .8 micron PET 6 micron to 3 micron(SPA goes even thinner sub 1 micron I believe)
PVC 10 to 8 microns?

Then you have how the energy is stored or absorbed or refected at the skin to capsule hold down ring and center screw if there.  I think even the speed of sound in the PET etc might make a difference in LDs

Every thing counts you spacing your hole size yor depth your volume. and it is not easy to understand.  I don't understand capsules yet but I keep learning.  At the distances capsules work at air flow is "funny"

The only company that reskins its capsules that I know of is gefell.
AKG and Neumann sell new ones.

A capsule is a SYSTEM so there is no easy answer.


aluminum vs. gold vs. nickel vs. brass plated caps...
« Reply #2 on: January 10, 2005, 10:58:02 AM »
thanks gus!

ive never heard of the SPA matieral though, what is that?
also, does using a thinner matieral have its negative reactions too? or were nothing available for the m7 caps and the like at the time but the thicker pvc?

do they have to re-tool their machines and equipment to be able to apply a different material? or was the reason for different metals purposely trying to get a specific sound?

how are you going about researching this topic? im *highly* interested, but the lack of material (meta is great, but hard info like books and sites) are obviously lacking.
i'd like continue the journey to capsule understanding, so please share any info resources you have!

thanks again.

...has a 'gold sputtered capsule for vintage sound'...


aluminum vs. gold vs. nickel vs. brass plated caps...
« Reply #3 on: January 10, 2005, 02:30:06 PM »
You can use either nickel, gold, or aluminum for evaporation or sputtering on plastic-like materials, for example, PVC or mylar. But you can also use aluminum, nickel, or titanium or whatever as a solid metal diaphragm. The soild metal diaphragms tend to be used on measurement mics. They are usually omni mics which need a high-tuned diaphragm == high tension. The tensions get a bit high, and they are also hard to manufacture, as the diaphragm size goes up. I am not sure of a big sound difference between using gold or nickel to metalize a diaphragm - I've tried both on the same backplate and had no difference that I could tell. Nickel sticks to the mylar much better and easier than gold, unless you have everything really, really, clean and are really lucky they day you run them. That is why sometimes you see people with re-diaphragmed mics with nickel instead of gold. If you saw that other than on my mics, though, it wasn't me that did it. I have only reskinned my own mics.

It is almost impossible to re-use the diaphragm material if you pull it off. If you have a diaphragm glued to the backplate (for example, the M7... or my capsules), it is tensioned then glued. Then the tensioning ring is cut off. If you remove the diaphragm, you have nothing to re-tension it with - plus it will likely stretch where the glue is holding it on, no matter how careful you are. If you have a diaphragm that is clamped but not glued to a retaining ring (some Chinese mics, for example, the Apex 460), it is almost impossible to re-tension it for the same reason - there is nothing to clamp on to. If the diaphragm is glued to a retaining ring, as you flatten the ring out with the clamp screws, the diaphragm re-tensions itself as you tighten the clamping ring down. Often, though, the diaphragm is what screws up on a mic capsule, so that would be replaced.

Likely, if you are getting a re-skinned M7, you will normally get Mylar. PVC is harder to work with (at least it was when I tried making PVC diaphragms), and is not as common. The K47 capsule uses mylar now, as well. I am not sure if they changed to mylar partways through the production years of the U47 but it wouldn't surprise me.

SPA is Stephen Paul - he was one of the mic gurus that pushed diaphragm thicknesses down rather seriously, along with a bunch of other microphone work. He passed away just over a year ago, unfortunately.


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