Soliloqueen's k87(k67) and k47 capsules

[rogs]

Another option is to consider doing the EQ externally, further down the signal chain.
If you're recording, most DAWs have pretty extensive EQ options.
For live situations, I've experimented with some line level EQ (some notes here: CEQ mic EQ system )
The advantage over internal passive EQ is that you don't have to worry about adding noise early on in the signal path.
Component noise added at line level, with little (if any) following gain is much less of a concern.

It's also possible to make more nuanced bandpass filters, rather than the 'brute force' single order passive filters can tend to apply.
Disadvantage is that you need to have access to the signal path....... I think most mic channel strips include insertion jacks these days ?....

 

[Andresound]

Anyone try a flat 47 in a Rode Classic I or II, or other bright tube mic? Would it just be a drop in replacement?

I have a RODE CLASSIC 1 with a flat 47, and it sounds great. Have left it in there. I have 2 Classic 1's, so easy to compare.

 

[blue_luke]

Absolutely, the post i made earlier today in the other thread. Just need to tune the circuit.

Which thread? Mine?
Today was a very good day for information gathering thanks to many individuals here on this forum!

 

[kingkorg]

Which thread? Mine?
Today was a very good day for information gathering thanks to many individuals here on this forum!

Yup.

 

[Paul W]

Has anyone measured the off-axis FR of a flat 47? Is the relationship between its on- and off-axis FR similar to that of an original 47, modulo both being flattened? Do the changes made to flatten the FR affect on- and off-axis response similarly?

 

[AUDIO FREQ]

I am saving and patiently waiting for her C800G capsule. It's going to be amazing I bet!

 

[kingkorg]

Has anyone measured the off-axis FR of a flat 47? Is the relationship between its on- and off-axis FR similar to that of an original 47, modulo both being flattened? Do the changes made to flatten the FR affect on- and off-axis response similarly?

Major update:
Here's SQ's "flat" k47 (red) against original Neumann's k47(blue). I honestly believe Ari's capsule is improvement on the design. 180° rejection is even better than the original. The shape is spot on, it's just that flat k47 is gentler in the midrange.

Yes. The original is hypercardioid, flat k47 is as well but to a lesser degree, a notch towards cardioid.

 

[soliloqueen]

Yes. The original is hypercardioid, flat k47 is as well but to a lesser degree, a notch towards cardioid.

It's about five decibels less sensitive in the rear than the regular k47 but with the same exact shape

 

[soliloqueen]

qc is done, international orders going out

 

[soliloqueen]

when the site comes back up, note that b-stock capsules are NOT sold as-is with no warranty. They're b-stock, not rejects. They should have at least one fully working side. You are still entitled to an exchange if your b-stock unit doesn't have one fully working side. it is essentially equivalent to buying a single-sided unit.

 

[Paul W]

Yes. The original is hypercardioid, flat k47 is as well but to a lesser degree, a notch towards cardioid.

I'd forgotten you'd posted the 180 degree plot (attached), but was more concerned about side rejection. (Mostly for quieting reverb in poorly treated spaces.)

Looking at the 180 degree curves, it looks like the flat 47 has better rear rejection in the treble but a little poorer in the bass. (Is that to be expected from a somewhat less narrow hypercardiod?)

(I'm wondering if I should wait for the accurate 47, for its narrower pattern, and use EQ to make the on-axis response flat when I want.)

 

[kingkorg]

I'd forgotten you'd posted the 180 degree plot (attached), but was more concerned about side rejection. (Mostly for quieting reverb in poorly treated spaces.)

Looking at the 180 degree curves, it looks like the flat 47 has better rear rejection in the treble but a little poorer in the bass. (Is that to be expected from a somewhat less narrow hypercardiod?)

(I'm wondering if I should wait for the accurate 47, for its narrower pattern, and use EQ to make the on-axis response flat when I want.)

This is pretty typical rejection curve for LDC cardioid/hypercardioid. You would get a better looking graph with somewhat better rejection in a real anechoic chamber, but you wouldn't record in one, so...

You can't really view mics that way. No mic pattern will help with untreated room. Graphs like this, or polar pattern graph help realize where a mic has most rejection, so you know how to place it against unwanted sound source. If you mic a tom, how to place it so you get most rejection from cymbals. But even then cymbal sound will bounce off tom head and come straight into capsule at 0°.

Hypercardioid vs cardioid vs even shotgun won't really help with room reverberation unless it's coming from one direction. Which would be a very weird room. Those things are for the most part misconception. Microphones are not lasers, no matter the pattern.

Low end rear rejection is bad for any mic, not due to the specific mic, but because sound wavelength gets too large. Low end is omni by the nature. Most companies don't publish plot bellow 125hz or even 250hz in their PP graphs because of this.

Best you can do is use a good pencil condenser like km184, or obviously, and stereotypically SM7b at very close proximity. Good end adress mics have much, much better rear rejection and off axis coloration. Also, by the laws of physics the closer you get to the mic, the quieter background noise will be. Inverse Square Law, to dumb it down - for every halving in distance mic/source, you get 6db more rejection.

There's a reason i came up with mic in the following thread. Autrian Audio freeware pattern plugin is something to think about. Lately i've built many dual output mics around different capsules for this reason:

https://groupdiy.com/threads/better-180°-rejection-for-dual-diaphragm-capsules-hybrid-second-order-cardioid.82758/

 

[blue_luke]

Kingkorg,
You have seen my ramblings and thinking as of late on some other posts I made lately.
I am thinking exactly of conducting the experiment you are doing right now but I want to build a twin capsule mic à la AKG C24 / Neuman SM69 etc... but with one driver for each side of each capsules.
Nevaton makes such a mic.

For this build I intend to use Arienne 'flat 47' and Jules OPA alice op-amp board.
I will start experimenting with some chinese capsules retired from some APEX 460 mic I modified.

I am not after getting anything historically correct or model specific, just something that work well, and I think this combination would be excellent. (flat-47 and OP Alice board)
Eventually, if needed I will design my own amps to do complete justice to Arienne's work.

For those who don't know what we are talking about check this YT VDO here I think it's Jules by the way...


I am debating with myself and some other members if it's worth to make the upper capsule rotatable compared the bottom one.
The Nevaton mic does not rotate I think... Actually I have just checked their site and this is basically what I want to build: http://nevaton.eu/product/nevaton-mc-50/

The consensus seems to be don't bother and keep the capsules at 90° from each other, and I tend to agree, but I found one case in a live recording situation where you would want the caps in line.
Let's say we have a singer, or instrument with a wide and unpredictable dynamic range, then we can apply the old trick of recording on two tracks with say 10 to 20 db of gain so if a channel clips, the other would remain clean, albeit at a lower volume, and this can be stictched later in post.

Dunnit many times....

I hope I am not polluting the OP, if so, just move it somewhere else, but I think it's relevant to your discussion.

 

[blue_luke]

OOPS! I will keep the VDO posted above on, it is still interesting, but this is the one I had in mind:

 

[Paul W]

This is pretty typical rejection curve for LDC cardioid/hypercardioid. You would get a better looking graph with somewhat better rejection in a real anechoic chamber, but you wouldn't record in one, so...

You can't really view mics that way. No mic pattern will help with untreated room. Graphs like this, or polar pattern graph help realize where a mic has most rejection, so you know how to place it against unwanted sound source. If you mic a tom, how to place it so you get most rejection from cymbals. But even then cymbal sound will bounce off tom head and come straight into capsule at 0°.

Hypercardioid vs cardioid vs even shotgun won't really help with room reverberation unless it's coming from one direction. Which would be a very weird room. Those things are for the most part misconception. Microphones are not lasers, no matter the pattern.

Low end rear rejection is bad for any mic, not due to the specific mic, but because sound wavelength gets too large. Low end is omni by the nature. Most companies don't publish plot bellow 125hz or even 250hz in their PP graphs because of this.

Best you can do is use a good pencil condenser like km184, or obviously, and stereotypically SM7b at very close proximity. Good end adress mics have much, much better rear rejection and off axis coloration. Also, by the laws of physics the closer you get to the mic, the quieter background noise will be. Inverse Square Law, to dumb it down - for every halving in distance mic/source, you get 6db more rejection.

There's a reason i came up with mic in the following thread. Autrian Audio freeware pattern plugin is something to think about. Lately i've built many dual output mics around different capsules for this reason:

https://groupdiy.com/threads/better-180°-rejection-for-dual-diaphragm-capsules-hybrid-second-order-cardioid.82758/

I do understand the inverse square thing and rely heavily on it, and I don't expect miracles w.r.t. polar patterns but my understanding is that some first-order directional patterns are a little bit better than others at rejecting off-axis sound from random directions. (Reverberation is more of an issue for me than bleed because I usually record at most 1 acoustic instrument or vocal at a time.) Looking at Eargle's The Microphone Book it seems that a hypercardioid's Random Efficiency is lower (better off-axis rejection) than a super's, but only negligibly (.25 vs .268), both being a little bit better than cardioid or f8 (.333 each).

 

[elskardio]

I ordered a pair of flat 47 capsules 1 year ago... and finally had time to install them today in my FET847s
Beautiful balanced sound!
Thanks again Arienne for making these available to the DIY community.

 

[Paul W]

OOPS! I will keep the VDO posted above on, it is still interesting, but this is the one I had in mind:

JLI also sells the dual-channel circuit (populated board) and the breakout cable for a dual-out microphone, for a whole lot less than the Endora microphone kit. There are Instructables how-tos about building mics with those circuits.

It's probably better to take that discussion over to kingkorg's aforelinked hybrid second-order mic thread, though.

 

[mrgrooves666]

qc is done, international orders going out

Ah excellent, can't wait

 

[micolas]

when the site comes back up, note that b-stock capsules are NOT sold as-is with no warranty. They're b-stock, not rejects. They should have at least one fully working side. You are still entitled to an exchange if your b-stock unit doesn't have one fully working side. it is essentially equivalent to buying a single-sided unit.

Hi,Ari!
The same conditions as the B-stock K47 capsules (functionality, price, warranty) will apply in this case as well
Arienne k87?
Thanks!

 

[kingkorg]

I do understand the inverse square thing and rely heavily on it, and I don't expect miracles w.r.t. polar patterns but my understanding is that some first-order directional patterns are a little bit better than others at rejecting off-axis sound from random directions. (Reverberation is more of an issue for me than bleed because I usually record at most 1 acoustic instrument or vocal at a time.) Looking at Eargle's The Microphone Book it seems that a hypercardioid's Random Efficiency is lower (better off-axis rejection) than a super's, but only negligibly (.25 vs .268), both being a little bit better than cardioid or f8 (.333 each).

I'll take simplest example. Two capsules of the same type one is cardioid, the other is hypercardioid.

Cardioid will reject most from the rear 180°, hypercardioid will reject most from 120° and 240°, but way less from 180°. The amount of total reverberation which is diffuse, that arrives to both capsules is the same, it's just that they will arrive from different angles. Energy must be conserved.