Question about diaphragms and possible build?

[tjjrx7]

Hello all.

I am new to microphones, but I have been playing around for electrostatic loudspeakers for years, and I would like to build my own capsule. While I understand the general working principle, there are plenty of parts that make absolutely no sense to me.

Perhaps the biggest one is metalizing the diaphragm. Obviously you would need to make the diaphragm conductive, but why metal? Why not a carbon layer like we do with electrostatic speakers? I feel like there is an obvious answer, but I can't put it together.

 

[soliloqueen]

Hello all.

I am new to microphones, but I have been playing around for electrostatic loudspeakers for years, and I would like to build my own capsule. While I understand the general working principle, there are plenty of parts that make absolutely no sense to me.

Perhaps the biggest one is metalizing the diaphragm. Obviously you would need to make the diaphragm conductive, but why metal? Why not a carbon layer like we do with electrostatic speakers? I feel like there is an obvious answer, but I can't put it together.

i believe someone here tried this. maybe something to do with mass and stiffness? with an electrostatic speaker, you need to drive the diaphragm. with a capsule, it just needs to pick up sound.

 

[pmfalcman]

There are several threads/discussions on this subject here.
Just search for graphite, graphene diaphragm.
Happy reading

 

[OPR]

Hello all.

I am new to microphones, but I have been playing around for electrostatic loudspeakers for years, and I would like to build my own capsule. While I understand the general working principle, there are plenty of parts that make absolutely no sense to me.

Perhaps the biggest one is metalizing the diaphragm. Obviously you would need to make the diaphragm conductive, but why metal? Why not a carbon layer like we do with electrostatic speakers? I feel like there is an obvious answer, but I can't put it together.

One reason for metalizing diaphragms particularly with gold is longevity, as it doesn't break down or oxidize. Mics used for vocal recording come into contact with bodily fluids which contain corrosive elements such as salt among other things.

 

[k brown]

One reason for metalizing diaphragms particularly with gold is longevity, as it doesn't break down or oxidize. Mics used for vocal recording come into contact with bodily fluids which contain corrosive elements such as salt among other things.

But un-metalized polyester ('Mylar') doesn't break down or oxidize either.

 

[tjjrx7]

There are several threads/discussions on this subject here.
Just search for graphite, graphene diaphragm.
Happy reading

That did the trick. Im thinking about making a 50mm diaphragm mic using some left over gold wire mesh as the back plate. I have a couple tricks I have developed to keep wire mesh stators taught and stable for headphones and speakers. Here's hoping that it is stable enough for a microphone.

 

[k brown]

50mm diaphragm?

 

[OPR]

But un-metalized polyester ('Mylar') doesn't break down or oxidize either.

It's also not conductive.

 

[Paul W]

That did the trick. Im thinking about making a 50mm diaphragm mic using some left over gold wire mesh as the back plate. I have a couple tricks I have developed to keep wire mesh stators taught and stable for headphones and speakers. Here's hoping that it is stable enough for a microphone.

As I understand it, wire mesh seems inferior to a solid very very flat electrode (albeit with through holes and blind holes). You want most of the metallized area of the diaphragm very close to the electrode, to maximize the capacitance, and thus the capacitance difference as the diaphragm moves.

A woven wire mesh will have most of the wires weaving toward and away from the diaphragm, so that they're not extremely close at most points, and if the wire is round in cross section, even at its the closest points, the wire will curve rapidly away from the diaphragm in the cross-sectional direction.