DIY large condenser capsules using PCB + space blanket

[michaeljtbrooks]

I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!

 

[Whoops]

very cool,
how does it sound?

Do you have any sound samples comparing it to a well known LDC mic?

Thanks

 

[michaeljtbrooks]

I've not got a comparison to a well known mic, but here's how it sounds:
https://content.instructables.com/ORIG/F8L/NKGL/L24QAHLC/F8LNKGLL24QAHLC.mp3

 

[rock soderstrom]

I've already seen this on the micbuilders mailing list, I'm a silent reader there.

I am totally impressed by this project, this is real DIY spirit regardless of the result. (which is definitely worth listening to). Bravo, keep up the good work and keep us posted!

 

[Whoops]

I've not got a comparison to a well known mic, but here's how it sounds:
https://content.instructables.com/ORIG/F8L/NKGL/L24QAHLC/F8LNKGLL24QAHLC.mp3

Thanks for the file.
It sounds alright, it would be great to listen a comparison with a well known LDC mic so there's a reference.

Congrats for your work

 

[frobozz]

I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!

great project, what is the right "search" for the aluminiumised Mylar ? I have difficult to find it

 

[Murdock]

great project, what is the right "search" for the aluminiumised Mylar ? I have difficult to find it

I got my aluminised mylar foil from here:
Free Flight Supplies - Lightweight Covering Materials For Sale
You have to scroll down.
He has 5, 10 and 15 micron thick aluminised Mylar.
Nice guy to deal with.

 

[kingkorg]

The only issue i have with that supplier is that the mylar is heavilly crimpled, and is a nightmare to flatten it out.

 

[kingkorg]

I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!

Thanks a milion for this space blanket tip, quite nice material!!! Do you have any idea what the thickness is, or can you find out? I have some 5 micron stuff, this feels thicker.

 

[michaeljtbrooks]

I managed to get hold of a micrometer and measured it at 6µm.

I've found that sticking the conductive side to the faceplate seems to get better results than sticking the non-conductive side to the edge of the backplate.

If you're struggling with corners buckling up, then you can modify the design so that the backplate active area feeding copper trace comes off a side rather than a corner.

 

[Pariah Zero]

Before I saw this thread, I've been thinking about doing something very similar:

• The idea of using a PCB/perfboard for a backplate is a great one. I'm glad you shared it.
• I'm also glad I've got confirmation that a space blanket can work
  • I thought it would, and since aluminum doesn't corrode that readily, it seemed to be a decent substitute vs gold-coated mylar, especially since a maintenance reskin wouldn't be an issue.
• I've got a micro lathe, so I was going to use Aluminum stock to turn out a capsule - consciously avoiding brass because it makes a bit more mess than I'm willing to deal with at the moment...

It gives me some ideas to chew on while I work on my ribbon mic; hopefully I'll have something to show in a month or two.

The other big question is if it's going to be worthwhile to try to find something on Alibaba (I'm not sure I could use 1 kg)

It does remind me that I have (or at least used to have) some 47 µF polypropylene foil capacitors. Those things are filled with 6µm aluminized film, and a 47µF film capacitor ain't small. I seem to recall they're about 62mm long and 62mm in diameter, so there may be plenty of foil to be had... definitely worth a search. If not, well, for anybody interested, and I can find the buggers, I'll let you know if the film is useful - if so, you know where to get plenty.

 

[kingkorg]

I managed to get hold of a micrometer and measured it at 6µm.

I've found that sticking the conductive side to the faceplate seems to get better results than sticking the non-conductive side to the edge of the backplate.

If you're struggling with corners buckling up, then you can modify the design so that the backplate active area feeding copper trace comes off a side rather than a corner.

Is there any way you could share the link of this particular 6 micron space blanket. The ones i keep buying are all 15 micron.