Wednesday, April 23, 2014

Schoeps V4 - Not what you'd expect from Schoeps!



$3,000 for the Schoeps V4, a cardioid only condenser microphone with no bells or whistles. I'll give you a moment to think about it. Oh, and remember, it's a Schoeps.

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OK. That should do it. As you may know, Schoeps doesn't do anything halfway. I expect there was, first, some arm twisting from within the company to even entertain the idea of a vocal studio mic. And why bother to position a small diaphragm design as a Studio Vocal Microphone? 


Vocal mics are, almost without exception, Large Diameter mics (LD). Or are they? The Schoeps CMC641 is a Small Diameter (SD) mic. You've probably heard it on voice since you were born as a boom mic for film dialog. Dialog is…voice!


Schoeps CM51/3
In fact, this is not Schoeps first time at the modified SD capsule. They have been using modified SD capsules since at least 1951 when they produced the CM51/3. 

(Seen here courtesy of http://www.schoepsclassics.de). 

It bears a striking resemblance to the V4. As a rule, properly designed SD mics fare better than LD mics when it comes to diffuse field sound that arrives as off-axis sound that inevitably get to the diaphragm. I guess the thought here is that in the highly controlled acoustical environment of the recording studio, these reflections are reduced or eliminated by the acoustic treatment. 

OK, but what about not so perfect acoustic environments? And why do people still gravitate to LD mics for vocals, even when they're recording in untreated or improperly treated bedrooms, living rooms and basements across the globe?

Presumably, because no one told them not to.

Schoeps V4 Polar Plot
Essential in a successful design, is the lack of aberrations in frequency response regardless of the angle. Easier said than done! Beamy mics are a dime a dozen. You'd think that someone would have backward-engineered a great mic and be squirting out knock offs prolifically. So far, not that I've heard. I had the V4 here for three weeks and I like it on just about anything. Do your own homework and read the document written by Schoeps' Managing Director Helmut Wittek about this mic. Helmut is also the Head of Technical Development at Schoeps. 




Schoeps' Helmut Wittek
Before I began writing, Schoeps' Helmut Wittek and I passed several emails. Basically, me asking questions about the design details, he responded, "The decision that it should be a cardioid only was very early and also relates to our ideals as only the native cardioid can be that perfect. A switchable double membrane can never be that perfect. Polar diagram and frequency responses of the V4 actually are so perfect that it cannot be said that it was not as perfect and natural as the MK4. It is just a bit different. The MK4 was made for a natural concert hall reverb whereas the V4 is tailored for a studio acoustical environment which doesn’t mean that they don’t perform well the other way round." 

Schoeps V4 Capsule

Try, as I did, I could detect no lobes or beams and the shoulders of the pattern roll off nicely, with a natural high frequency loss as you move out of the main pattern. The white beveled ring, that you can see on the left here, surrounds the capsule and apparently allows capsule to mimic desirable attributes of a large diaphragm mic, while not calling attention to its less desirable problems. If you want a closeup, just click on the pictures.





Schoeps V4 Frequency Response
I asked Helmut to provide some technical details about the engineering behind the beveled capsule and what it does. "The surround allows the small membrane to act like a large membrane, because the path lengths are then doubled. We have to deal with the situation where the pressure gradient properties only exist for frequencies not up to 6 kHz -7 kHz, but only for frequencies of 3 kHz - 4 kHz."

Helmut went on to say that, "In every pressure gradient microphone, there exists a frequency region below a specific frequency where you have the pure pressure gradient, and above that frequency where you have a pressure buildup effect, that also creates a directional microphone, but at that point, it's no longer acting like a pressure gradient microphone. So an MK2 (omni) and MK4 (cardioid) act very similarly above 8 kHz. Damping the back entrance of the membrane prohibits these frequencies from getting to the back of the membrane so the mic acts as a pressure microphone. If you let them through, you'd have some very severe aliasing. You are taking the subtraction between two points that are more than half a wavelength between each other. That is not a good signal." 


The graph below demonstrates the 0/90/180 degree responses. First notice that this graph is not one of those "made pretty by a graphics artist for a brochure" set of curves, it's the real deal. Notice the linearity of the 0 degree (top line) response. Also notice how well the 0 degree and 90 degree responses track, and the rise of the lower 180 degree curve (-25 dB to -15 dB) between 2 kHz and 4 kHz.




"It's a miracle that it works so well.", says Helmut, "And now we have it in the V4, but we shifted the aliasing frequency of the mic one octave lower and that's very much the same as a large diaphragm microphone. So we still have the properties of a small membrane microphone with regard to the action of the membrane itself. We haven't changed the movement of the membrane, how it moves on different points, the stiffness of the membrane and other parameters. These are still the good properties of a small membrane."


Helmut also notes that the trade off between noise floor (self noise) and evenness of frequency response. "Traditionally, Schoeps opts for damping out every single peak of the frequency response at the cost of some higher noise floor, but at a value which is already very low. So we could reduce the noise floor by two or three dB, but the cost would be an uneven frequency response." Evenness of frequency response regardless of axial position or orientation and a naturalness of tone are hallmarks of Schoeps microphones. 

So, even though the retro design of the grille demands attention, the V4 is not a mic that asks for attention by sounding deliberately colored. Exactly the opposite. It has a crisp and clean sound without beams and peaks that compromise recording and make mixing a nightmare. The V4 does like its space. Getting closer than 4-5 inches with my voice resulted in a cloudy, proximity laden response that was unflattering. Don't eat this mic!


Producers Video - Bob Bragg
I took the mic to Bob Bragg at Producers Video on the slopes of TV Hill here in Baltimore. I knew Bob would appreciate hearing the mic and I also know he battles some very serious RF from the downlobes of the broadcast arrays on the two towers. We did run into some low level demodulated audio with the V4 in one of his booths, but I never heard any in my studio. 

On my voice he suggested, dropping 125 Hz a dB or two and maybe adding a dB or two around 5-6 kHz. That's a formula that's worked on my voice for years. Different voices will require different attention.


I need to make a point here. Just because the Schoeps V4 is called a voice or vocal mic doesn't preclude it from being used on anything else. It worked well on my two vintage Fender guitar amps; a Vibrolux and a SuperReverb. So well so that it picked up a nasty little tube rattle in the Vibrolux with excellent detail. I have found that my pair of Schoeps CMC641 are often my first grab for many things; acoustic guitar, drum overheads, saxophone, guitar amp, acoustic bass, hand drums, flute choirs, orchestras, and cicadas on the front lawn. 


I think the V4 would be an excellent addition to take up some of this work, especially in rough and ugly acoustical climates where the nonlinearities of lesser mics would result in an unattractive, beamy phase wash.

The Schoeps V4 can handle 144 SPL, so there are no worries about putting it in front of some very loud sources. 

With a selfnoise of 15 dB-A and a sensitivity of 16mV/Pa, the Schoeps V4 may not be the quietest mic in the locker, but it's quiet and sensitive enough. 


A Neumann U 87Ai has a selfnoise of 15/12/14, and a sensitivity of 20/28/22 depending on pattern. The Schoeps V4 also has no sign of a "tizzy" high frequency response that so many Sino-built mics are plagued by. 

Come back later and I'll have some links to audio files so you can hear the V4.

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