Pronomic SCM-1

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kingkorg

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I converted one of the stock capsules yesterday to hypercardioid by widening holes in plastic backplate. It knocked of 7k peak. However you ged a dip at about 4k, which happens with stock hypercardioid as well.

If anyone is interrested, diameter of wider, hypercardioid holes is 2mm.

I can rapport  that grille in front of the membrane affects just response above 10k. I even made several custom grilles to see what happens. Not much, it's mostly response above 10k that changes.

The biggest changes come from spacers betwen backplates, and holes.
 

RuudNL

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I suppose that you enlarged all the holes to 2 mm?
It would be interesting to see what happens if you only change a couple (4 or so) of them.
Maybe the change wouldn't be so drastic, but there is a chance that the 4 KHz dip wouldn't be so prominent.
 

kingkorg

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Yes. All four of them. Sure, one can try with less or smaller holes.

When i measure the capsule outside stock body, in a faraday shield the capsule is flatter and that dip at 4k is way smaller.

I gues when the holes are enlarged the acoustucs behind the capsule make more impact, and we all know those vents are not perfect. I'll post some measurements i made.
 

kingkorg

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So i got old style capsules, and two of them couldn't be more different. One is insanely hyped, and the other is ''classic'' with 8k peak.

The one that was hyped had only one spacer between the backplates instead of two! One thing to have in mind when you order these!
 

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kingkorg

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And this is  the same cardioid capsule  attached to the stock body (blue) vs detached in a Faraday shield with same electronics (green) unsmoothed.  Notice the dip/peak that body creates.
 

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kingkorg

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And this is cardioid vs hypercardioid (hypercardioid purple). The hip at 6.5k is caused by the body.
 

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RuudNL

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Wow, that is some pretty interesting information!
By the way: I noticed that the capacity of those capsules varies widely!
I have some as low as 30 pF, while others are 42 pF.
 

micro1_de

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Hi, all,

It would also be interesting to close some holes to get a wide cardiode.  May be the dips will be away also!?

Reiner
 

kingkorg

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Just stumbled upon this, Kenny Arnoff uses Mojave  which have ''old'' type Pronomic, MXL, bla, bla, bla capsules. And he found them useful on snare and toms...

https://youtu.be/SMqR57OCZto?t=10m57s
 

RuudNL

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Just out of curiosity, I used an 'old' capsule and enlarged four of the eight holes in the plastic backplate to 2 mm.
The difference is dramatic: the bump around 7-8 KHz is a lot lower now, but there is a very sharp dip around 6.5 KHz.
Also the midrange seems to be boosted (1-2 KHz), while the lower frequencies are rolled off.
I am sure that the real capsule designers are now rolling over the floor laughing, when they see us struggling!
Green = original, Red = modified capsule.
 

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kingkorg

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Never got midrange boost. But i did get that dip. Lows should be actually stronger. Maybe try widening all of them.
 

kingkorg

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Ruud, if you have two of these spacers between the backplates try removing one, that solved the dip problem for me.
 

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Icantthinkofaname

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So how does the hyper cardioid backplate mod sound? EDIT: Reread some posts and it's clearly the old Pronomic (though correct me if I'm wrong).

I'm think I might just get the  newer Oktava MK-012 "film set" (hyper cardioid capsule) SDC (which apparently  implement the Dorsey mod stock), unless someone can recommend me another good hyper cardioid SDC that isn't super bright or peaky within the same or lower price range (which is somewhere around $300 Canadian or $225 USD I think).

kingkorg said:
The blue one is with one spacer instead of two (stock)
Wow that's quite the difference. Seems like the mids aren't  as present, and the high end is slightly more present but you don't have the huge dip obvious. So one spacer is good for hyper cardioid, but bad for cardioid?
 

micro1_de

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@Icantthinkofaname

What do you think about MBHO KA500 HC. Might be what you search. Phantastic hypercardiod capsule . Price is a little bit higher.

Reiner
 

Icantthinkofaname

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Think this hyper cardioid mod would work in other cardioid SDCs assuming they used a similar backplate? I'd be pretty interested to see how it works with something like the iSK Pearl (rebranded iSK BM-88) since that has a 25mm diaphragm (so it's a "medium" diaphragm I guess, still an instrument mic, looks kinda like an Oktava MK-012 copy I'd say). If I pick one up I'll take open it up and post some pictures, it's been on my list of cheap gear to look at for a while. Though if it's anything like the CM-20 or Little Gem cardioid capsule it has a pretty significant rise around 7k.

And I'll probably just get the MK-012 since it seems to be one of the better price for performance SDCs (I've heard the same about a ton of things like the iSK Little Gem, but that has a pretty big rise around 7k and the super cardioid cap also has an additional spike around 5k (though I've heard people compare it to a modded MK-012?), but I know I've liked every MK-012 sample I've heard for dialogue/speech, not terribly fond of my iSK CM-20C still but it's far from neutral sounding) so it's probably the best choice.  I'd prefer to keep price as low as possible since I don't know how much I'd actually use it. Plus I have to also buy a portable recorder that does at least 96/24, and possibly a small preamp like a FetHead Phantom (and probably a used budget shotgun mic for outdoor recording). Basically my planned use case is micro/no budget videography (imagine comedy sketches and the like) and occasionally voiceover (though I still need to make proper acoustic treatment).
 

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