Soliloqueen's k87(k67) and k47 capsules

[soapfoot]

Agreed as well

I haven’t installed the first K47V I bought and am tempted to buy another once the in-house metal is ready, just because you seem so much more excited by those

Would love to get your honest sense on whether the in-house metal iteration will be substantially better than the first run

 

[ZHOUJUN]

we're doing final bug hunting in the g code for all the parts. we've already found and fixed most of the bugs in the backplates, but check out this funny bug in the validation samples for the M7 mount. I'm using fusion 360, so instead of doing nurbs modeling like a sane person would in solidworks or something, i just used a ****-off huge fillet command:
View attachment 145772

That means that there is a line boundary in this curve where there shouldn't be a line boundary. A human would look at this and realize that it's from using a fillet command and understand that this is supposed to be an uninterrupted surface, but CAM software does not understand the concept of shape. It is programmed to generate toolpaths that ensure that each face fits the drawing within a certain percentage error. It looks at this and goes "oh, two faces!" and generates ideal toolpaths for each face. But it doesn't consider the area in between the faces, and it cannot create an infinitely small boundary between the faces, so the result is:

View attachment 145773
sorry for the dust i'm handling them with my fingers in my home office which i know I shouldn't do.

the CAM can't generate correct toolpaths for the shape, even though it can do the faces fine, so this will need to be manually altered.

I'm not going to go out of my way to hand-polish the mass production m7 mounts or anything, so I wanted to figure out how good we could get a purely machine finish on these parts. The results are not too shabby:
View attachment 145774
View attachment 145775

considering that this is not one material, but brass that we nickel plated after without re-processing, this is pretty good for a machine only finish. this should be nice and cheap for us to do at volume and, most importantly for a small 5ish-person shop, almost zero human effort-time

I think there shouldn't be much demand for this M7's mount, and it won't have an impact on the sound. Additionally, many finished products come with this mount, such as Thiersch, 3U and WET. It would be better if the cost is invested in capsules. Because we look forward to your new K47 being launched soon.

 

[Roman B.]

I think there shouldn't be much demand for this M7's mount, and it won't have an impact on the sound. Additionally, many finished products come with this mount, such as Thiersch, 3U and WET. It would be better if the cost is invested in capsules. Because we look forward to your new K47 being launched soon.

I disagree: At least here in Europe you can't find any properly made M7 mount for less than 60$ plus VAT, shipping etc.

So if Ari was able to offer a well made M7 mount for less, I see good reasons for her (and the market) to proceed with this.

Although the price for the amazing Thiersch STW7 capsule is astonishingly low (only 310 € plus VAT etc.), it doesn't come with the STS7 holder. It needs to be ordered separately (see your picture with all three heights available).

 

[ZHOUJUN]

I disagree: At least here in Europe you can't find any properly made M7 mount for less than 60$ plus VAT, shipping etc.

So if Ari was able to offer a well made M7 mount for less, I see good reasons for her (and the market) to proceed with this.

Although the price for the amazing Thiersch STW7 capsule is astonishingly low (only 310 € plus VAT etc.), it doesn't come with the STS7 holder. It needs to be ordered separately (see your picture with all three heights available).

This is sold individually, I have bought it several times, more than 50 euros a piece is still acceptable to many people, I mean such a simple accessory does not take more time, and may not make any money at all.

 

[soliloqueen]

I like precision milling the mount because I can design it in such a way that the outer diameter is referenced directly to the minor outer diameter of the m7, so regular screws can be used instead of grub screws and they will simply bottom out against the bottom of the head exactly when the M7 is secure. Makes things easier for DIY Folk and manufacturers

 

[soliloqueen]

in case you guys are wondering about the numbers on manually-binned k47 capsules

 

[Roman B.]

Here's a a real life measurement comparison of a U87/67ish mic (RuudNL EF86 based circuit with simplified NFB) with chinese K67 (RM branded) capsule (pink) and the same mic using Ariennes current K87 capsule (yellow). Note: Aris capsule has even been rolled off a bit more in the air band and still shows a much better high end! As the chinese K67 was too dark, I had lowered the capacitor value down to 30pF in the NFB-loop to make it work at all. Not needed anymore, got the cap back to a reasonable value with Aris capsule (90pF) - and a very nice FR, that does neither look nor sound hyped or sibilant:

PS: The narrow swings of the chinese capsule above 8k maybe would have looked better with the Basotect/melamine foam collar, that I had added after installing Ari's capsule (see HERE). So in this respect, the comparison is not completely fair.

 

[micolas]

Here's a a real life measurement comparison of a U87/67ish mic (RuudNL EF86 based circuit with simplified NFB) with chinese K67 (RM branded) capsule (pink) and the same mic using Ariennes current K87 capsule (yellow). Note: Aris capsule has even been rolled off a bit more in the air band and still shows a much better high end! As the chinese K67 was too dark, I had lowered the capacitor value in the NFB-loop to make it work at all. Not needed anymore, got the cap back to a reasonable value with Aris capsule - and a very nice FR, that does neither look nor sound hyped or sibilant:

PS: The narrow swings of the chinese capsule above 8k maybe would have looked better with the Basotect/melamine foam collar, that I had added after installing Ari's capsule (see HERE). So in this respect, the comparison is not completely fair.

View attachment 146378

We thank you, Roman, for sharing your measurement results and conclusions with us. They are really very useful.
K67 RM is the capsule from mic&mod?
Edit:
It is obvious that the circular piece of foam could not fix the RM capsule anomaly in the 5.6 - 6.9 KHz range which is very "Anti-Neumann" ish

 

[Roman B.]

We thank you, Roman, for sharing your measurement results and conclusions with us. They are really very useful.
K67 RM is the capsule from mic&mod?

Yes! RM stands for Replica Microphone; it came with the kit, but you can order it w/o capsule as well (which I did for my matched pair second RuudNL-67). So after having found out the best configuration, I'll be building the second mic accordingly in one go.

I just finalized two standardized mic audio recordings with the RM and Ari's K87 capsule, that match all the other variables of my graph:

MIC AUDIO EXAMPLE 1

MIC AUDIO EXAMPLE 2

Try not to look at the file names first and just listen (the "M67AA" file is of course the one with Ari's capsule).

 

[micolas]

Yes! RM stands for Replica Microphone; it came with the kit, but you can order it w/o capsule as well (which I did for my matched pair second RuudNL-67).

Well, now everyone knows exactly why this cheap rebranded RM capsule should be avoided and why we don't like this business model. You better buy a second hand B2-PRO, you have a good 797 K67 capsule, you have a donor body and good parts specific to microphone projects, you just need to get a suitable transformer.

 

[MaxxDM]

The AA file sounds more like being in the room, frequency response aside.

My personal experience with the 2000's K67 from Neumann I had bought vs. the early original capsules is something akin to what I hear there.

I would have to compare with my old capsule, to be sure, but it sounds pretty good.

The 'real' test for me is to record something at 2-3 meters distance, including piano

The older capsule had more 'reach', and I don't know what causes that.. compliance of the diaphragm, or tension, or resonance/damping... ??

because people mostly use LDC's for close-up vocals, you can sort of get away with murder with those chinese capsules, but for 'orchestral' applications, things become more obvious IMO.

 

[micolas]

I just finalized two standardized mic audio recordings with the RM and Ari's K87 capsule, that match all the other variables of my graph:

MIC AUDIO EXAMPLE 1

MIC AUDIO EXAMPLE 2

Try not to look at the file names first and just listen (the "M67AA" file is of course the one with Ari's capsule).

I listened in a blind test.
Example 1 sounds detailed, natural, realistic, credible, spectral and polar. It has dimension, listening creates an almost visual image for me.
Example 2 shows fractures, irregularities in the smooth continuity of the FR, it lacks information in some areas of the spectrum and other frequencies are exaggerated. It sounds artificial.
Some tests with voices, acoustic guitar, other sources, but real, not played through an audio system, would be of interest.
A good male voice would be extremely relevant, especially for the problematic mid-high range.

 

[Roman B.]

Well, now everyone knows exactly why this cheap rebranded RM capsule should be avoided and why we don't like this business model. You better buy a second hand B2-PRO, you have a good 797 K67 capsule, you have a donor body and good parts specific to microphone projects, you just need to get a suitable transformer.

Well, it depends. When you want good things cheap and time is irrelevant, then yes. But when you are making money actually recording stuff, the sourcing of material is time consuming, prone to errors - and money in that price range won't be a big deal. Plus the M&M kits are well assembled, the tubes are hand picked by RuudNL for low noise (which they are!) and I preferred the kit's Electro Harmonix EF86 in that specific mic over every other tube in my locker including NOS Telefunken EF806S. So apart from the capsules, I was happy using the M&M kits as a starting point.

 

[micolas]

Well, it depends. When you want good things cheap and time is irrelevant, then yes. But when you are making money actually recording stuff, the sourcing of material is time consuming, prone to errors - and money in that price range won't be a big deal. Plus the M&M kits are well assembled, the tubes are hand picked by RuudNL for low noise (which they are!) and I preferred the kit's Electro Harmonix EF86 in that specific mic over every other tube in my locker including NOS Telefunken EF806S. So apart from the capsules, I was happy using the M&M kits as a starting point.

I admit that we are all impatient and often we are tempted to buy a complete kit, with selected components, parts and replace only the worse parts.
But when I have these compulsive, addictive urges, I remind myself that I assembled the last kits when I was a child, decades ago. In addition, I like to make point-to-point test builds, in the air, without pcb and to experiment with various components, this gives me the greatest pleasure, it gives me special satisfaction

 

[micolas]

the tubes are hand picked by RuudNL for low noise (which they are!) and I preferred the kit's Electro Harmonix EF86 in that specific mic over every other tube in my locker including NOS Telefunken EF806S

I didn't know @RuudNL hand selects the tubes for this kit himself.
(maybe tubes or other sensitive, vital components for other kits as well?)
If I'm not mistaken he designed some kits for m&m (maybe for more commercial brands as well?)

 

[Roman B.]

I didn't know @RuudNL hand selects the tubes for this kit himself.
(maybe tubes or other sensitive, vital components for other kits as well?)
If I'm not mistaken he designed some kits for m&m (maybe for more commercial brands as well?)

I think it's just the tubes that he is selecting. And yes, all of the current M&M kits are designed by him. I am really fond of his (replacement) circuits; they are elegant, simple, effective and sound great, in principle. RuudNL has my deepest respect and is a very nice guy.

But maybe we should stay away from another round of considerations regarding the shady aspects of the M&M marketing dpt and get back to the original topic: The greatness of Ari's capsules !

 

[micolas]

But maybe we should stay away from another round of considerations regarding the shady aspects of the M&M marketing dpt and get back to the original topic: The greatness of Ari's capsules !

You are absolutely right!
@soliloqueen , I'm sorry, I apologize, we got a bit carried away by the side waves and deviated from the topic of the thread.

So the bottom line is that the Arienne K87 sounds great!

(and I'm running out of patience, my pair of K87s ordered before Christmas and shipped very quickly, still haven't arrived, I don't even know where they are )

 

[soliloqueen]

i don't really like speaker tests like this, but both sound decent. I don't hear any of the broad differences micolas hears. B has that weird almost papery sound in the high end that real neumann capsules have. i have mixed feelings about this aspect of the k87, but it is replicated faithfully here. vocals in A have odd harmonics that come and go in the lower mids. the sound in B is more consistent. A just sounds kind of chesty and roomy in a way that I don't think is good. the high end of A sounds really weird. perc has too much 7k in A. I would think my capsule is B. the shentuo capsule (M&M) has this issue where it sounds almost hollow that I hear in the vocals in A, though this is clearer on proximity in a real recording. the perc segment shows seriously lacking low end extension in A. A is practically high passed, which is another thing that makes me think my capsule is B. the difference in low end extension is huge for between two capsules of the same type. Like 2 or 3dB at 70hz. this would make sense, as the difference in tension between my vintage spec k87 and the m&m is almost 300hz, lol.

i opened them up in reaper to AB more directly and you know it's ugly when you have a bass-heavy instrument and the transients are the same volume and the sustain is visibly different:


that's murder

edit:
had the tabs open backwards, fixed.