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Stereo Technique with MK41 or other super-cardioid Microphones

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beenjammin:
Apologies if this has been discussed in another thread. I've searched but haven't come across anything dedicated to stereo techniques with the MK41.

(As an aside, my application is nature recording (bird species), spot-ambience, effects, et al. I typically record ecological soundscapes and have used the MK2 in AB for this application to good effect. I need something with more reach and focus; something mobile which I may run handheld to capture a single bird call/song, street corners, fountains and all other sorts of sounds.)

I know the MK41 does very well in MS with the MK8, but I wonder if there might be suitable stereo configurations with two MK41s.

Does it work in ORTF? NOS? DIN? Something else?

heathen:
You might want to play around with this: http://www.sengpielaudio.com/Visualization-EBS-E.htm

I think a fair number of people on here use DINa with hypers/supers, but I don't remember the measurements for that off the top of my head.

beenjammin:

--- Quote from: heathen on June 16, 2018, 12:52:48 PM ---You might want to play around with this: http://www.sengpielaudio.com/Visualization-EBS-E.htm

I think a fair number of people on here use DINa with hypers/supers, but I don't remember the measurements for that off the top of my head.

--- End quote ---

Thanks, I've been playing around with that applet.

My concern with two MK41s in stereo is over how to treat the null of the super-card's pattern. Our own David Satz posted the following on the REP forum:

"That's crucial for stereo imaging, and it is why a pair of supercardioid microphones must be angled somewhat more narrowly than cardioids would be--to avoid having the null of the left microphone aimed at the direct sound at the right of the stage and vice versa. I'd try 100 degrees as a starting point."

(http://repforums.prosoundweb.com/index.php?topic=7164.0)

I guess this is why the MK41 works well as a run and gun technique in MS: the null of the 41 may be absorbed by the body of the recordist standing behind the microphones.

I'll try to rent a pair of MK41s so that I may play around with angles. I think MS with a MK41/MK8 will suit me best, but want to check out near-coincident configurations first. 

kuba e:
I am sorry, I didn't read all details in discussion you linked. My English is bad, it would take me a long time. I will try to write the basic rules, it could help to understand stereo recording.

The first rule for stereo recording with pair of mics with directional pattern:
- the bigger spacing between mics, the wider stereo recording.  the smaller spacing between mics, the more mono recording.
- the bigger angle between mics, the wider stereo recording.   the smaller angle between mics, the more mono recording.

Spacing is creating stereo image by sound's time difference. Angle is creating stereo image by sound's level difference. Try first bigger angle (e.g. 90 degrees) and small spacing (e.g. 10cm) and the second small angle (e.g. 25 degrees) and bigger spacing (e.g. 35cm). Both variants should give very roughly the same stereo image but with different atmosphere. Compare it.

The second rule:
The microphone is the most sensitive on it's axis. When you need the sound source to be more prominent in comparison to the surroundings, aim the microphones more at the sound source (smaller angle, bigger spacing). Sounds, that are coming out of the mic's axis, are quieter in the recording. Another way to achieve more prominent sound source compared to the surroundings is to get closer to the source (we get a sound level drop of 6 dB per doubling of distance).

You can combine different spacing and angles to get it right for you.

If you have time and energy, the stereo recording theory is very nicely explained in Michael Williams document Stereo Zoom:
http://microphone-data.com/media/filestore/articles/Stereo%20zoom-10.pdf

DSatz:
Hi. A couple of thoughts:

- If you're coming from a background of recording with spaced omni microphones, I think you'll find that recording with two coincident or closely-spaced supercardioids gives a fundamentally different overall impression. It's not just a variation by degree from what you're used to. The listener's brain goes into a different mode of listening, because the sense of space and the ability to localize direct sound sources are so different between the two kinds of recording. They're both called "stereo" but they're so different in their effect that I sometimes think there should be different terms for the two approaches. (A/B vs. X/Y comes close; "intensity" vs. "arrival time" differences are involved, but those are ugly terms and anyway, those two principles of operation aren't mutually exclusive in most cases.)

With spaced omnis, if the live environment in which you made your recording was rich and spacious, a similar feeling can be manifest when your recording is played back. It's like bringing that _environment_ into the room where the playback occurs; you may feel as if you are wrapped or "enveloped" by that environment, even with only two channels and two loudspeakers. This encourages a mode of listening in which sensuousness and the color of sound are the main offerings. It invites you to turn off certain critical tendencies, and just take a bath in the sound. If the material being recorded is highly complex, it will be blended and softened and the edges rounded off by this type of recording. That can make it more palatable and atmospheric--sometimes primitive and mystical, even--at the cost of some clarity and specificity. That's where judgment and experience come in, since you may not always want that particular tradeoff.

With directional microphones, particularly coincident supercardioids or crossed figure-8s, you can get a very clear "stereo image"--a representation of the direct sound sources that's consistent over space and time, and that involves your knowing (on some level in your brain) where the direct sound sources were relative to the microphones. This offers much better support if you're consciously trying to grasp the specifics of the content that's being delivered. But esthetically it is a very different type of experience. The emphasis is more on the direct sound sources and where they are and what they're doing; the "atmosphere" is reproduced more quantitatively than qualitatively. Its tradeoff is that it puts more of a cognitive burden on the listener, but with a greater payoff in specific information if the listener chooses to engage that way. But it's not usually as intuitively persuasive as a good spaced-omni recording.

There are crossover and compromise approaches. I like certain aspects of both typological extremes, so I'm very drawn to those crossover approaches in many recording situations. Those include the use of "subcardioid" microphones (in the Schoeps line, that would be the MK 21 and MK 22--the so-called "wide cardioid" and "open cardioid" patterns respectively) with an approach to angling and spacing that's derived from ORTF stereo recording.

- "Reach" is a problematic concept, especially where stereo recording is concerned. A fact of physics that surprises a lot of people is that the highest directivity you can get from a "first-order" microphone (with a single capsule and no special signal processing) only gets you a 2:1 "distance factor" relative to an omni. In other words, if you find that the optimal balance of direct to reverberant sound is obtained when an omni mike is 3 feet from something, then a hypercardioid would give you that same quantitative balance of direct and reverberant sound at 6 feet. No first-order microphone pattern can ever give you that same "3-foot balance" at any greater distance; no microphone can "zoom in on" a more distant sound source and make it seem that close.

For a number of technical reasons, a pair of good supercardioids may well be your best choice when you are forced to record in stereo from all the way into the reverberant sound field. Certainly NOT shotgun microphones, which have highly irregular off-axis response at high frequencies, and no better than supercardioid directivity at low and mid frequencies (i.e. they're useful only when they're close enough to the sound source to pick up enough direct sound on axis so that you don't care about the residue of off-axis sound). But even good supercardioids can't compensate for excessive recording distance. Directional microphones are, if anything, more sensitive to their exact placement than omnis are.

- All that said, there's an interesting variant on omnis that can produce surprisingly good results sometimes, and that is to embed the membranes of each microphone in the surface of a sphere (see attached photo). I wonder whether you've tried this technique with your omnis. (Add-on sphere accessories are available for various microphone diameters.) It's another one of those adaptations or compromises that I spoke of, but this one completely preserves the spaciousness and "envelopment" aspects of spaced-omni recording, while increasing the clarity and directness of the direct sound sources.

Just as food for thought.

--best regards

P.S.: The attached photo shows a Schoeps omni capsule mounted on a Colette active cable and surrounded by a sphere accessory. But such spheres can also slide over the capsule when the capsule is mounted directly on the microphone body (amplifier). The important thing is for the surface of the sphere to be "flush with" the front edge of the capsule. -- This technique works only for omni (pressure) transducers. It would block the rear sound inlet of a pressure-gradient (directional) capsule and mess up both its polar response and its frequency response.

P.P.S: I meant to point out--when you're looking in Williams' charts or on Sengpiel's site or on http://www.hauptmikrofon.de/, be aware that supercardioid and hypercardioid have dictionary definitions which any given microphone probably won't fit exactly. The Schoeps MK 41 isn't exactly a supercardioid; it's like 2/3 supercardioid and 1/3 hypercardioid. Neumann calls their small hybrid a hypercardioid, but it's also in between hyper- and super- (with a slightly different recipe from Schoeps). Similarly, Sennheiser calls theirs a supercardioid, but it has about the same pattern as Neumann's hypercardioid, etc., etc.

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