DIY Condenser Mic Capsule

[byacey]

Has anyone actually made their own condenser capsule? I would be interested in discussing this further with someone who has. This looks like something I might tackle, although I think I would make the preamp based around a FET; less heat and better long term stability.
Bill Y.

[buttercup]

Hi Bill

Did you read Kent's articles on the 'DIY mic articles up-again' thread?
I think a few people including myself want to try but the only person
I know who has tried is Ashley Stiles who is a vintage mic supremo
in England but without an Internet/email connection!
As I am away from home I don't have his number to hand but if you
type his name into a search engine you will find the articles he wrote
on tube mics for one of the recording magazines.
I'm sure he said he had a go at making a capsule.

Giles

[robflinn]

I used to correspond with an Italian guy who made his own condenser mic including capsule. I was impressed by this, although I never heard it. He said he used a sweet wrapper for the diapragm. The kind that is see through plastic with an aluminium layer on one side. He sent me some pictures in which it looked good. Unfortunatley I lost contact when my PC crashed & I no longer have his email address.

[hodad]

re gum foil: there is a little info on making your own mic ribbon out of gum foil at this link
http://groups.google.com/groups?q=ri...nix.com&rnum=1
If the link doesn't work, go to rec.audio.pro at googlegroups & search for ribbon gum wrapper & you'll find it.

[ciminosound]

That post about chewing gum wrapper was posted by Scott Dorsey. He knows his stuff. He regularly writes DIY articles for major magazines. About a year ago he wrote an article about rebuilding the onboard electronics in the Chinese mics into a high quality FET/transformerless pre. Here's the article.. Scott Dorsey Chinese Mic Upgrade
HO,HO,HO!
[img]graemlins/beerchug.gif[/img]

[byacey]

Thanks for the replies.
I have read Kent's article that he has posted, but I find it lacking in description and details, but there appears to be enough info to get started. I was just inquiring if anyone has pursued making one of these, and what problems they encountered so I don't make the same mistakes!! One other question I have is since gold is heavier than aluminum; would using aluminum sputtering on the diaphragm increase transient response due to reduced mass, or is the difference so small that it's a rainbow chase?

[mr_a_perkins@hotmail.com]

I came across a list of places where they make metallized foils.
Maybe this could help?

http://www.tremnet.com/main/extheadi...%20User&l=ENGB ;)

[audiochick]

Hi. Thanks for bringing this subject up by the way. I have been thinking about microphone design a lot lately. Particularly capsule design!!

Anyway, seems to me that the standard of gold sputtering or vapor deposition of gold onto polyester film is a standard in the industry for a reason (though I have heard of titanium diaphragms used in shotgun mics). I could be mistaken but I am under the impression that originally capsules were made from aluminum but it turns out to be too fragile whereas polyester film is a bit more rugged and able to handle short bursts of energy while still retaining it's shape (aluminum would be permanently deformed and in need of replacement in some cases). So maybe in going back to aluminum you would be reinventing the wheel kind of thing. Now those diaphragms were made entirely of aluminum if I'm not mistaken so maybe your aluminum sputtering idea would be a different story, I don't know. But just to note, gold does have a slightly higher conductivity than aluminum and also a resistance to corrosion (doesn't tarnish).

If you want to increase transient response, you can use a thinner film material (though you should use caution there, may be difficult to mold and retain its shape). Particularly since you haven't done this before; if you were a seasoned professional, well, you wouldn't be asking about all this. Now don't get me wrong, I haven't done this myself, I'm learning all I can before I take that step just like you so we're in the same boat.

There are also different factors to think about depending on whether this is an omnidirectional or cardiod capsule and dynamic or condenser microphone.

I have two suggestions for you. One is that you get the AES Microphone Anthology and/or go to a library and look through old Audio Magazine articles from say 50's/60's. You will gain a wealth of knowledge from these if you haven't sought them out already.

Lastly, do you have access to a metal lathe? It is my understanding that this is the only way to machine metal parts which require such a high amount of precision.

[HiString]

Aluminium will eventually suffer from surface oxidisation, which I imagine would render a delicate diaphragm almost unusable. It may be worth investigating whether any aluminium alloys exist that will resist oxidisation.

Just more food for thought ;)

[Kev]

Welcome to audiochick ! [img]graemlins/wave.gif[/img]

The AES Microphone Anthology is a good idea if you are very keen on this stuff.

I have Microphones vol 1 to vol 27 (1953 - 1979)
and
Speakers Book 1 vol 1 to vol 25 (1953 - 1977)
Speakers Book 2 vol 26 to vol 31 (1978 - 1983)


... obviously there are newer volumes out but it is the old stuff that sets the knowledge base.
I just realised those dates .... somewhat date me.
You guys that are starting out now have it so good with all this info on tap.