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[klaus]

Yes, we all know about that "Chinese Treble". The term should be added to the audio dictionary.

[Piedpiper]

I listened to the advertised recordings and both have some "chinese treble" in common.
If it's the mic or anything else in the recording chain I can't decide.

I only listened to one and I heard the same, though they mentioned adding a high shelf on a Pultec, though it's beyond me why they thought that was a good idea. No accounting for taste... I'm hoping to take a visit to their factory which is a couple hours from me sometime if they will allow me to demo it.

[gtoledo3]

It’s supposedly European origin, but who knows.

It makes me wince when a manufacturer wants to sell something for thousands of dollars and has a problem disclosing particulars about tube type or capsule. Don’t be coy, you know? It’s going to come out anyway. In some cases, “I get” protecting tube types, but it’s still annoying IMO. If you don’t tell me what’s in it, I’m not buying!

That mic strikes me as such a poor idea on multiple levels, and from a first time builder at that. Sticking two EF86 or EF86 related tubes in a mic body, and placing the preamp stage IN the mic seems to have “bad idea jeans” written all over it. People are enthused, so there’s that.. Interested to hear one in person nonetheless.

http://www.nbc.com/saturday-night-live/video/bad-idea-jeans/n9937?snl=1

[Noah Scot Snyder]

I don't find it mentioned on the manufacturers website if it's platinum sputtered on (mylar) foil or a massive platinum diaphragm.
I suspect it's sputtered, so this would not be so special as it doesn't matter what type of metal is used for the process.

On the webpage they say it is " custom handmade premium platinum membrane capsule", so that must mean it's sputtered.

[Recording Engineer]

I’m going to guess platinum on Mylar (like the couple I previously mentioned), as I’ve yet to see a platinum foil without Mylar any less than 25-microns; maybe they do, I just haven’t seen it yet.

I’d imagine a platinum foil would have to be much, much thinner (maybe somewhere around the 1-1.5 micron range?) to be appropriate for a microphone diaphragm; to make the mass about as typically seen with other metal diaphragms.

[Recording Engineer]

Ok, found some 0.1-micron platinum, but nothing in between so far. I can only imagine the price too!

[AusTex64]

The Mastering Lab tube mic was directly coupled to its preamp. Also the Requisite Audio mic has the preamp included in the system. The Chandler mic is not unique in that regard.

[Marik]

And I can’t imagine a better conductor than gold. Since so little gold is actually deposited on a membrane,  it doesn’t seem like raw material cost would be significant.

Mickey,

The layer of deposited gold is in the range of only 100 Angstroms, so it has pretty low conductivity to start with, which is not a priority here, as it is a very high Z circuit, anyway.

But that may defeat the purpose of using a very thin and agile metal diaphragm instead of a plastic one that usually is twice as thick or thicker than a metal diaphragm.

Klaus,

The effect of thickness here can be quite deceiving. The density of Ni is 8.9g/cm^3, and of Mylar only 1.38g/cm^3. That means that twice as thick Mylar will still be more than 3 times lighter than Ni counterpart (and more compliant). On the other hand, there will be other factors such as mass of loading air (which is moved along with the diaphragm and which is frequency dependent) and also stiffness of the air trapped between diaphragm and backplate, which works as a spring, effectively damping the diaphragm. Those may (or may not) negate all those mass and compliance differences.

Best, Mark Fouxman
Samar Audio Design
Omni8 Audio

[klaus]

I do to argue with the weight difference between similar-dimensioned nickel and Mylar diaphragms. But your claim that a Mylar film twice as thick as nickel would still be more compliant (i.e.flexible) than nickel is something I would like to see proof of. It does not seem logical.

[Kai]

But compliance comparisons...

When building a microphone it's not the goal to have as high tension as possible on the diaphrag. In fact the opposite is true, the lowest tension that still gives a stable result is desirable to extend the low frequency response.
I once talked to Mr. Wutke from Schoeps here in Karlsruhe, and he told me that is what they do with their figure of eight and cardiod capsules. Omnis are different.
Metal could have a point over Mylar in long-term stability in that regard, but I'm only (educated) guessing here.

[Marik]

But your claim that a Mylar film twice as thick as nickel would still be more compliant (i.e.flexible) than nickel is something I would like to see proof of. It does not seem logical.

Klaus,

The Young's modulus (i.e. a measure of the stiffness) for Ni is 190x10^6 PSI and for Mylar 1x10^6 PSI. In other words, Mylar is by far more compliant material.

When building a microphone it's not the goal to have as high tension as possible on the diaphrag. In fact the opposite is true, the lowest tension that still gives a stable result is desirable to extend the low frequency response.

Kai,

But with lower tension then you are losing top end response. The carefully chosen optimum tension/tuning frequency for a given capsule is always a part of a system comprised of capsule acoustical chamber parameters, time delay network, resonator system (if any), and desired voicing. It will also affect capsule's sensitivity.

Best, Mark Fouxman
Samar Audio Design
Omni8 Audio

[Kai]

But with lower tension then you are losing top end response.

In fact you linearize the bass.
Using as low tension as possible is a quote from Schoeps's chief engineer Mr. Wutke with whoom I had close contact. I even tested a prototype mic for them at that time. Schoeps is located in my hometown.

Specially on fig. of eight mic's the low frequency response is of major concern, as the pressure gradient (the pressure difference between front and backside of the capsule / diaphrag) gets lower with frequency.
The stiffer the diaphrag the less it will follow the air movement.
Most REAL (single diaphragm, not double-cardiod) fig. of eight condensors roll off below 200Hz or even higher because of this.

Schoeps CCM8 reaches 50Hz with a soft rolloff to only -6dB (often compensated by the proximity effect when used as spot mic). There is no problem in the high range with this mic, it's ruler flat up to 15kHz and sounds very nice and rounded.
The mic uses mylar sputtered with gold, but in former times Schoeps built mic's with pure nickel diaphragms with comparable accoustic properties.

You are right with cardiods, they present a complex system using a combination of even more then the mentioned accoustic effects, needing to be properly tuned to each other.
Still, low tension is desirable here if you need to cover the full range.
Klaus prefers the lower tensioned specimen of the Neumann capsules e.g., for their fuller bodied sound.

This low tension close to the possible is one of the main reasons for cardiod capsule failure, there is no big margin like with higher tensioned omnis.

[Marik]

Using as low tension as possible is a quote from Schoeps's chief engineer Mr. Wutke with whoom I had close contact. I even tested a prototype mic for them at that time. Schoeps is located in my hometown.

Kai,

As always, the evil is in details. In order to compensate for high frequency loss (as a result of diaphragm' lower tension) Schoeps uses resonator system, which is just another way of implementation...

Specially on fig. of eight mic's the low frequency response is of major concern, as the pressure gradient (the pressure difference between front and backside of the capsule / diaphrag) gets lower with frequency.
The stiffer the diaphrag the less it will follow the air movement.
Most REAL (single diaphragm, not double-cardiod) fig. of eight condensors roll off below 200Hz or even higher because of this.

The single diaphragm fig8 condenser is very specialized capsule and there were only a few more or less successful models on the market. Of course, I was talking about cardioid capsules.

In general, to make a fig8 single diaphragm we need a mass controlled system, so the diaphragm is tuned to a very low frequency. In this case the sensitivity will drop with rate of 6dB per octave going up. At the same time the pressure gradient forces on the diaphragm will increase twice per each octave. That's how we get a linear frequency response. That's why ribbon microphones naturally have a linear response up to the point of cancellation where the front to back distance is equal to the frequency of wave length and pressure gradient is 360 degree out of phase.

Condenser single diaphragm works as mass controlled only above the frequency of tuning resonance. Below it is a stiffness controlled system. In order to make a flat response we need to introduce acoustical resistance. The lower the tuning resonance, the less acoustical resistance we need, the more output such capsule will have for a given linearity. But of course, as you rightly mentioned, here we are faced with diaphragm stability problems, which is the main limiting factor.

You are right with cardiods, they present a complex system using a combination of even more then the mentioned accoustic effects, needing to be properly tuned to each other.
Still, low tension is desirable here if you need to cover the full range.
Klaus prefers the lower tensioned specimen of the Neumann capsules e.g., for their fuller bodied sound.

This low tension close to the possible is one of the main reasons for cardiod capsule failure, there is no big margin like with higher tensioned omnis.

As I mentioned before, the diaphragm tensioning depends on the desired voicing and very much depends on entire system it is part of. In general, all the capsules are tuned differently. For example K47 is considerably low, K67 quite a bit higher. On the other hand, CK12 way higher than either. The reason being the first two are aperiodic designs and introduce quite high acoustical resistance and damping to the diaphragm, while the CK12 is a multi-chambered and rather resonant system.

Best, M