Quick DIY dual output LDC

[kingkorg]

I had some scrap parts from mics i modded so i made this mic just to try out the concept. Not the cleanest build, but it works like a charm.

Its made to work with free Lewit software, but i like to use it with Townsend Sphere plugin, which is still available for free for demoing purposes.

The body is from Sterling audio ST51 30$ used.

The capsule is two cardioid st51 capsules with removed unused halves (backplates) and joined together, so any two sided capsule will work. Halves don't need to be electrically insulated.

Now, the 2 pcb boards come from two Subzero SZC-100. The same thing as MXL603 or Takstar CM60 which costs 28$ with delivery! Takstar one is SMT though. All of these pcbs should fit.

I was even so lazy that i didn't trim the pcbs, so they are bent.

Pcbs are Schoeps circuits biased for minimum distortion. This is the only mod done to them.

Membrane leads from capsule are connected to coupling capacitors of each pcb, backplate(s) is connected to ground.

I even have cool internal switches for pad and hpf.

Outputs from pcbs are going to individual xlrs.

I even went one step further for using with Townsend software and made impulse response which is used before plugin to match their emulation with my mic to real u87 i had. After this step other emulations in the software are in the same ballpark as originals. Sphere plugin has this kind of correction as well to flatten out their capsule which is k67.

Now the emulating is something we can debate on, specially with this Frankenstein, but the end point is that this is most interresting mic i could have made for about 100$ that is amazingly good sounding, versatile, and a lot of fun.

And it doesn't even need any software, it's cool stereo, clean mic with dual side capsule that is actually used in Manley Reference.

 

[kingkorg]

The other angle

 

[emrr]

Cool.  It surprises me more people haven't experimented with dual output mics. 

 

[rmaier]

Cool indeed! The ability to manipulate the pattern after the fact seems really useful.  How do you like it as a stereo mic?

 

[kingkorg]

Works awesome on it's own. Realy great.

 

[kingkorg]

Guys i am ecstatic how this mic turned out, and i can't recommend you more to try this out.

Here are some outtakes from the recording i made this summer, and you can here it with some compression and no other treatment as a drum room mic. I used it as a stereo mic. There are examples without emulation, just direct, with u47, u87 and c12 modeling using Townsend Labs software,

Just for reference there is a take with my u47 replica, which is basically heavily modded Nady 1050. However that mic is used as a mono mic, turned in another direction, so it's a bit of apples and oranges, but just to get the idea.

There is a take of final drum buss sound with u47 model in Townsend software, just compression, no EQ on room mic!

The room is pretty dark sounding, as the kit is placed in dead booth with doors left open. So what you hear is what's left coming out from the booth.

The rest of the kit features SubZero SZC-100 with bias adjusted for lowest THD and with HF attenuation (Microphone Parts style) on toms and snare bottom.

AKG c3000 with electronic HF boost removed (my 5 minutes mod) snare top with PAD.

Røde NT3 with electronic HF boost removed, simmilar issue to c3000 on overheads

Alctron MC410 rebiased + polypropylene capacitor  with 797 audio C12 style capsule.

Only untouched mic is Shure Beta52 on kick.

I am really looking forward for some feedback.

https://app.box.com/s/f7rz8ll5rjthkphw5y798w73wqqcngl7

 

[kingkorg]

No one?

 

[emrr]

I haven't listened, but will echo your interest again in dual output mics.  My latest captures have been thunderstorms with an MKH 800 Twin and a Neumann omni.  Interesting using the 800 as-is for stereo versus using it as a figure 8 in mid-side with the omni mid.  It's been cool using them as the mid in MS also for pattern adjustment after the fact, kind of like having a zoom lens that can be adjusted as needed, within a song. 

 

[kingkorg]

It's been cool using them as the mid in MS also for pattern adjustment after the fact, kind of like having a zoom lens that can be adjusted as needed, within a song.

Great metaphor, exactly how i feel about it.

 

[jpsexton]

Very Cool!

So basically the Townsend Labs Mic is just a stereo LDC?

I probably have half of these parts lying around...

I may give this a try!  ;D

 

[kingkorg]

Yupp. Doesn't even have flat response, that is achieved with impulse response curve(eq) embeded in emulation responses.

 

[dab0815]

So i got the mics now and i got some questions here (sorry if i sound stupid here but im a first builder so please be indulgend)

you said you connected the Membrane leads from capsule to coupling capacitors  and to fet of each pcb
i think the capsule lead of each side is connected to where i marked the picture with the red circle in the attachment is that right? but then it seems on the picture of your build you go from there to another spot ( i think you wire connected the two spots where the capsule lead is connected to?)
could you please explain that to me? sorry when i dont know what the coupling capacitator and the fet is on the board  :-[

 

[dab0815]

then for grounding you told me in another thread "Connect grounds from both and ground backplate of the capsule."
judging from the pictures of your build i go from the grounding connections on the backplate (2) (that also goes to the xlr) to the metal of the mic chassis. and from the backside of R6 which i marked with (1) also to the chassis.
but where do i connect the grounding lead from the capsule?

 

[kingkorg]

i think the capsule lead of each side is connected to where i marked the picture with the red circle in the attachment is that right?

That is the spot.

Grounds are common on the mic, so which ever spot you pick it's ok. Chose shortest path to capsule backplate though. Avoid multiple ground connections.

So try it this way. Capsule backplate to one of the boards ground, closest possible spot, and just to one of the boards, not both.

Then from the existing connections of both boards on the bottom, which go to xlr, connect to ground pin of whatever connector you use. Then make sure that pin is connected to chassis of the mic. That pin (ground) is usually connected to screw termination of xlr connector. 

Make sure in the end that all parts of the chassis are grounded with a multimeter. Sometimes headbasket are attached just mechanically to the ground, it could be a weak link, so you might want to solder some jumper between grille and chassis.

Hope that makes sense. 

 

[dab0815]

Thank you for the fast reply. I think i can work with that. Just one more question.

you said you connected the Membrane leads from capsule to coupling capacitors  and to fet of each pcb

But its just the one spot each pcb i need to connect to and from there it gos to the fet and coupling capacitator right? Or do i need the capsule leads to connect to both the fet and the coupling capacitator at different spots on the pcb?

And if you could school me how to check the chassis is grounded with a multimeter (which i have) i would be thankfull too. Sorry all this is new to me but very exciting

Btw. I will use the original b2 pro body (the old one with interchangable head) and maybe later a nice unbranded one if everything works out fine.

 

[kingkorg]

But its just the one spot each pcb i need to connect to and from there it gos to the fet and coupling capacitator right?

Exactly, i've updated the original post, sorry for the confusion. The exact spot you marked on the picture.

B2 body has a grille with "mechanical grille connection" so i would make sure grille is connected to the board with a wire.

 

[dab0815]

Alright nice. I just took apart the b2 pro but im not too confident using the body as the head is sticked into the body and that part where all switches are like pad and  polar pattern switch cant be taken out without not getting the body to reattach to the head i think..
also inside that part there are already some electronics inside. So i dont know if i can use it and just soldier the  ground and capsule from below that part to the pcb. I know id loose the switches anyway thats ok but i dont think i can use the head anyway.. i will make pictures now and post them for you to see what i mean.. because i think from just the text it dont make too much sense does it?

EDIT: ok here are the pics. please read the description below each pic so you will know what is it that id like to know about it. THX! i hope it makes sense.

https://imgur.com/a/D7EPpMz

so if i use the head would it be possible to connect the red wires to the pcb for the capsule leads and the yellow one as ground and leave everything else as is? or would i need to desolder all the other connections inside and below the head connection first?

 

[kingkorg]

Easiest is to make a small hole in that black box, and stick the leads from capsule through it to the boards. Make sure the switches are also grounded, otherwise they might make some noise when touched, even though they won't be connected to anything.

 

[dab0815]

damn i didnt even think of that. thanks!

 

[dab0815]

Sadly after all the work it turned out that the pcbs didnt fit the b2 pro body because theyre too long..
so i ordered this microphone body with the shockmount and will wait with the build until the body arrives. hopefully i can fit everything in there and finish the build.