End-address condenser mic... thoughts?

[BoysRBackInTown]

Been thinking about end-address condensers lately. I have the Earthworks SV33, which I really like. It has a small 16mm electret capsule and that seems to work quite well. My question is whether or not you could build an end-address condenser with a 34mm LDC capsule? Or, as I'm guessing, would it be problematic because the back of the capsule would face into the body of the microphone, probably not far off the capsule deck? For sake of argument, I'm picturing a body similar to say, an RE20.
So, with end-address condensers, is an electret capsule the only solution?

Found this thread while researching Earthwork's mics, I am very curious in particular about how the Earthworks design of their more recent mics work (the ethos/icon). They both seem to use small diaphragm condensers (the ethos is a 14mm supercardiod electret). The Ethos seems to use an SM7B style grill design. That top would be difficult to simulate but I wonder if an SM7B clone body from ali coupled with an electret, some mesh and a tube design (3DP?) might get half of the way there.

I know broadcast mics like this are a bit of a pain to create and probably not worth it vs. a U87ai clone but I am very much interested in exploring something like this.

 

[kingkorg]

Found this thread while researching Earthwork's mics, I am very curious in particular about how the Earthworks design of their more recent mics work (the ethos/icon). They both seem to use small diaphragm condensers (the ethos is a 14mm supercardiod electret). The Ethos seems to use an SM7B style grill design. That top would be difficult to simulate but I wonder if an SM7B clone body from ali coupled with an electret, some mesh and a tube design (3DP?) might get half of the way there.

I know broadcast mics like this are a bit of a pain to create and probably not worth it vs. a U87ai clone but I am very much interested in exploring something like this.

View attachment 135835View attachment 135834

I made something similar with T.Bone BC500.

Those vents on Earthworks mics are carefully engineered. Whatever capsule you decide to use i would go with transparent mesh behind the capsule, like i did in this example to avoid disturbances in FR and pattern response.

 

[Barry Hufker]

Here is Sonodore's axial microphone with a 1" diaphragm... http://sonodore.com/LDM54.htm

 

[BoysRBackInTown]

I made something similar with T.Bone BC500.

Those vents on Earthworks mics are carefully engineered. Whatever capsule you decide to use i would go with transparent mesh behind the capsule, like i did in this example to avoid disturbances in FR and pattern response.

Interesting! Nice work Korg. How did it sound?

Yeah I imagine that it's no small task (Earthworks is very well designed). So you place your capsule at the end and have a transparent mesh behind. I wonder how one of the 14mm JLI Electrets would perfom in this case.

 

[kingkorg]

Interesting! Nice work Korg. How did it sound?

Yeah I imagine that it's no small task (Earthworks is very well designed). So you place your capsule at the end and have a transparent mesh behind. I wonder how one of the 14mm JLI Electrets would perfom in this case.

Sounds like intended. I have the luxury of tweaking both circuit and capsule, also measuring the result to confirm if i'm on the right path. I attenuated the high end peak a bit to get in the ballpark as sm7b, only more HiFi with extended both low and high end.

Sure, you can try those capsules, for darker sounding variant with built in FET maybe something like Primo EM200 or EM204. It comes down to taste. Bulky body behind the capsule helps a lot with the rejection, but it is crucial not to have much going on in close proximity behind the capsule to avoid resonances and reflections.

You can try 3dp something like this:

https://www.thingiverse.com/thing:3085428

Also take care, whatever is holding the capsule shouldn't have resonance, so then you hit the holder with capsule attached, it doesn't vibrate at some frequency.

 

[amplexus]

I once worked on two Lomo 19a19s one was amazing sounding the other one was nice

I came here to say Lomo also.

Even if OP doesn’t want to buy, that’s a very good sounding mic and worth a look for inspiration. Iirc that capsule is edge terminated, but it’s been a year or two since i’ve had one on the bench.

 

[rogs]

You can try 3dp something like this:

https://www.thingiverse.com/thing:3085428

I created and posted the 3dp files for that design some 6 years ago --- For those who'd rather just buy the same thing, and not print it themselves, it's available from Shapeways. See here: https://www.shapeways.com/product/EFE6MUJYM/34mm-ldc-mic-bracket?optionId=123657963

I've built several mics into BM800 bodies using that mount. Works very well -- and the rejection for cardioid is really quite good with that body (There's pretty open rear access to the capsule with that big headbasket!)
I've had no problems with resonance... and there are slots in the base, to alow for rubber grommets to be fitted. Helps with the isolation from the mic body.

These images give some idea of the mechanics involved....

 

[rogs]

For those who'd rather just buy the same thing, and not print it themselves, it's available from Shapeways. See here: https://www.shapeways.com/product/EFE6MUJYM/34mm-ldc-mic-bracket?optionId=123657963

Not any more! .... I hadn't realised that Shapeways has filed for bankruptcy, and appears to have stopped trading in the same way - for the time being at any rate.

THIS LINK to the .stl files is still valid ....... Has anyone got suggestions for alternative 3DP companies that do small quantities at reasonable prices?

 

[Barry Hufker]

I too recently found out Shapeways was no longer selling. They did indeed go bankrupt but their assets were purchased by another company. See the news article here: https://3dprintingindustry.com/news...s-manuevo-following-asset-acquisition-232193/

 

[rogs]

I too recently found out Shapeways was no longer selling. They did indeed go bankrupt but their assets were purchased by another company. See the news article here: https://3dprintingindustry.com/news...s-manuevo-following-asset-acquisition-232193/

Thanks for that --- looks like THIS company have taken over......

Prices are a little bit higher ... and shipping is around £15 minimum . (Shapeways were quite expensive for shipping as well. )

 

[Tim Campbell]

AKG 421 with a CT12

 

[Tim Campbell]

Or the opposite. A U47 with a B&K capsule

 

[OneRoomStudio]

I'm a little jealous of all your fun experiments, @Tim Campbell, haha. How did those sound?

 

[Tim Campbell]

Well I made the CT12 capsule a little darker for the 451 and it sounded like a 414. The U47 is Martin Kantola's. It sounds incredible but much more flat than a 47 like the most beautiful measurement microphone you've ever heard.

 

[ricardo]

Here is Sonodore's axial microphone with a 1" diaphragm... http://sonodore.com/LDM54.htm

View attachment 135855

This is an OMNI. Loadsa advantages for multi-tracking (and outdoors bla bla) but it will sound completely different from da cardioid LDCs yus punters like for close work.

You can make an omni with many of these advantages using a PUI 5024 capsule in my SimpleP48 circuit. You have to join.

 

[amplexus]

Another one to look towards for inspiration is the somewhat obscure AKG C5600- It's basically a ruggedized, single pattern 414 TL

It's been a minute since I've had one on the bench, but it's a great sounding, more or less compact end address mic. I believe it has a sort of conical baffle at the rear.

 

[pmfalcman]

I believe it has a sort of conical baffle at the rear.

Exactly.
A "sound dispersion cone".

 

[mrchapp]

Not any more! .... I hadn't realised that Shapeways has filed for bankruptcy, and appears to have stopped trading in the same way - for the time being at any rate.

THIS LINK to the .stl files is still valid ....... Has anyone got suggestions for alternative 3DP companies that do small quantities at reasonable prices?

JLCPCB has a 3D printing service too, which is dirty cheap: https://jlc3dp.com/

You can have 3D prints and PCBs in the same shipment.

 

[OneRoomStudio]

A weird one from the annals of history:
https://www.vintagemicworld.com/html/Mic of the month May 2020-RTV Condenser microphone.html

 

[rogs]

JLCPCB has a 3D printing service too, which is dirty cheap: https://jlc3dp.com/

You can have 3D prints and PCBs in the same shipment.

Thanks for this suggestion...I've just received a small shipment of 3 end address capsule mounts from JLC. Total cost - including shipping - was $3.56 !
Delivery took one week.....
That's a lot less money (and faster delivery) than Shapeways. These brackets (which are black resin) also seem to better quality than the Shapeways white nylon version...