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Gear / Technical Help => Microphones & Setup => Topic started by: beenjammin on June 16, 2018, 12:23:54 PM

Title: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: beenjammin on June 16, 2018, 12:23:54 PM
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?
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: 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.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: beenjammin on June 16, 2018, 01:48:44 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.

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. 
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: kuba e on June 16, 2018, 04:08:45 PM
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 (http://microphone-data.com/media/filestore/articles/Stereo%20zoom-10.pdf)
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: DSatz on June 17, 2018, 09:19:19 AM
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.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: goodcooker on June 17, 2018, 09:25:51 AM
I'll chime in since I've been running MK41s for a bit and used the hypercard capsule/setting on other mics.

Reconsider this - "I think MS with a MK41/MK8 will suit me best" - when you use a cardioid mid and mix 50/50 you end up with basically a pair of hypercardioid mics. When you use a hyper as the mid and mix the same you end up with a pair of Figure 8. This may or may not be exactly what you are after.

I tend to not use the fixed 90 degree angle DINa pattern (90 degrees/17cm) that was the conventional wisdom for running a stereo pair of hypers. I tend to run a slightly larger spread and a slightly more narrow angle usually between 20-25cm spread and roughly 70 degree angle. I feel that this retains the stereo image but gives more direct to reverberant ratio (more of the source, less of the surroundings) but still has the time arrival differences that make for a pleasing stereo image. I think with microphones like MK41s that have a very realistic off axis sound the spacing is more important than the angle. Of course this is for recording music mostly indoors.

I realize that for recording nature and ambient sounds you may need a different approach and I've always used more open patterns - omnis or subcardioids when doing ambient recordings since I think it sounds more natural.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: beenjammin on June 17, 2018, 12:04:51 PM
Thanks very much, DSatz and goodcooker.

DSatz: such an excellent post that nicely expresses what I love about AB, especially with omni. I am aware of the APE spheres and tried them once outside on one of those rare days with very little wind and loved the results. My only issue was how to use them in windy situations. I asked one of the US Schoeps representatives if the APE ball might work inside a W20 R1 wind screen as was advised against this approach.

goodcooker: very interesting approach to the MK41 regarding spacing and angles. Have you ever experienced issues with the microphone's null?

I'm not looking to replace my AB setup. I've been using this for a few years and am very happy with the results. My strategy is hike in somewhere, find a nice spot, hit the record button and clear out for as long as possible. My interest in another stereo technique is motivated by a desire to have something that works handheld while moving about. I'd like to be able to record things from birdsong to trains to interesting air conditioner units. Less ambient, more species/individual focused.

 
 
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on June 17, 2018, 01:16:46 PM
https://www.listeningearth.com/blog/recording-nature-sounds-with-andrew-skeoch
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on June 25, 2018, 04:43:41 PM
First a correction on Mid/Side.  I'll make some other comments in a following post.

when you use a cardioid mid and mix 50/50 you end up with basically a pair of hypercardioid mics. When you use a hyper as the mid and mix the same you end up with a pair of Figure 8. This may or may not be exactly what you are after.

The second part of the statement above (which I've bolded) is incorrect.

The only Mid/Side setup able to create a pair of virtual figure-8 patterns is one which uses a figure-8 Mid.. and in that case the Left and Right virtual microphone patterns are always figure-8 shaped regardless of Mid/Side ratio.  In that case, changing the Mid/Side ratio will change the angle between the two virtual 8's but will not change the shape of the virtual pickup patterns.  This behaviour (the virtual polar pattern remaining unchanged regardless of ratio) is unique to Mid/Side done with a figure-8 Mid microphone.  Use of any other polar pattern as Mid microphone means the resulting virtual polar patterns will vary in shape, usually in combination with with the change of virtual microphone angle.  The exception, and corresponding opposite behaviour, is use of an omni Mid microphone.  In that case the virtual pattern varies along with change of ratio, but the virtual microphone angle always remains a constant 180 degrees.

It is correct that a cardioid Mid, used in combination with any Mid/Side ratio which produces a useful stereo pair, will produce a coincident virtual pair with supercardioid-to-hypercardioid shaped sensitivity patterns.  The degree of supercardioid to hypercardioid-ness depends on the Mid/Side ratio used, but the virtual patterns will always somewhere in the supercard to hypercard range, and never actually reach cardioid or figure-8.

It is also correct that use of a supercardioid or hypercardioid Mid will also produce a coincident virtual pair with a supercardioid-to-hypercardioid like sensitivity patterns.  The degree of supercardioid or hypercardioid-ness still depends on the Mid/Side decode ratio used, but the patterns shift more towards the hypercardioid side.  They still never reach virtual figure-of-8 patterns for any stereo Mid/Side ratio, but they get somewhat closer.


Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on June 25, 2018, 04:53:08 PM
An additional note on dialing in Mid/Side ratios- Use your ears to determine what is correct, more than your eyes to read the ratio number.  In other words, don't worry what the ratio reads on your Mid/Side control, it's the sound that matters and that ratio display is quite likely lying to you anyway.

Why? 

The Mid/Side control assumes the use of equal sensitivity mics and matched gain between channels.  In addition to the Mid/Side ratio you specify in whatever control you are using, any difference in sensitivity between the Mid and Side microphones and any difference in recording gains between the two channels also affect the Mid/Side ratio.  This is an additive "in addition to" thing (similar to the total gain being the sum of all gain stages- such as preamp gain plus recorder gain), yet the Mid/Side control is blind to any other gain variables which preceded it, meaning that specifying a 50:50 Mid/Side ratio with your Mid/Side control may not actually produce a 50:50 output ratio. This is a commonly overlooked aspect here at TS where folks are quite often using Mid and Side microphones that have differing sensitivities and/or using more gain on the Side channel than the Mid channel to get optimal recorded levels.

If you mix by ear instead of dictating a Mid/Side ratio by number, you automatically accommodate for these issues.  Who cares what ratio number you end up with anyway? Optimizing for best sound is what matters.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on June 25, 2018, 06:42:35 PM
Apologies for my OT Mid/Side asides above.  Just wanted to get that stuff that out of the way.

What I mostly wish to contribute to the thread is to echo DSatz's comments on the fundamental difference in overall listening impression between A/B and X/Y microphone techniques - an excellent observation, well stated.  I especially perked up at the mention of "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."

The bit below may seem OT at first, but I'll explain further down why I think it applies.

I consider near-spaced microphone techniques commonly used around here as attempts at finding optimized middle-ground solutions which effectively bridge the gap between these two very different modes of recording and listening, without moving beyond the constraint of two microphones and two recorded channels.  This can work very well for live music, where we can achieve a respectable balance between immersive ambience, good clarity and sharp imaging using well considered arrangements of two microphones.  Yet I'm rarely completely satisfied with the results given the necessary compromises.  Once I became aware of how well each aspect can be addressed on their own, albeit at the detriment of the other, those compromise solutions all to often no longer satisfy either listening mode for me sufficiently.  Of course there are plenty of exceptions, but the general trend holds.

I want to try and better optimize for both modes of listening at the same time, so I break the listening experience down further and essentially use separate pairs of microphones optimized to more ideally capture these different aspects, then combine them afterwards.  I feel this results in a better overall result than trying to find a good "middle of the road" optimization using a single pair of microphones.  The trick is that this must be done in such a way that the separate pairs support rather than fight each other, and the devil is most definitely in the details with respect to achieving that.  It's easy to make a mess of it and just complicate things without really improving the end result.  Still, I commonly argue for this somewhat unusual approach here at TS.  That's partly because I feel audience-perspective music recording is a unique recording endeavor compared to other forms of recording- For one thing, audience perspective recording is typically done from a considerable distance from the source.  It represents a very ambient recording situation regardless of whether we like that or not. In addition, we have far less control over the situation and the techniques I'm suggesting provide some additional control and flexibility;  And lastly because I find the presentation more convincing for both "modes of listening" - I can mentally switch back and forth and get a better feel for both than I can with straight 2-channel near-spaced microphone techniques. 

I see these things as possibly being applicable to your nature and ambience recordings as well.

Consider what you are recording and what you want to convey to the listener.  Then consider recording approaches which are optimized for what you want to convey.  If it's relaying a feeling being there in that place with a convincing immersive ambience, a spaced A/B technique with open pattern mics such as omnis is hard to beat.  If its a clear and precise focus on a particular sound within a particular soundscape, a single microphone or a coincident (X/Y, Mid/Side) technique using highly directional mics like the Schoeps MK41's can achieve that.  If you want both at the same time, you may be able to find a "middle ground" near-spaced approach which works for both aspects without compromising either too much. Or you can optimize separately for each aspect, and make a composite recording which better portrays both of them.  All depends on what you want to achieve, and how much effort you want to put into it.

For what you are doing the composite approach would probably mean setting up a spaced A/B omni recording to capture the ambience, and focusing a single MK41 directly on the subject of interest from a not overly distant location.  If the direct sound from subject of interest has stereo qualities to it which you'd like to convey in addition to the atmospheric stereo ambience from the A/B pair, you might consider using both MK41 in a narrow X/Y configuration (or better, a Mid/Side setup using one MK41 plus a figure-8 such as the MK8). Narrow so that neither mic of the pair is very far off-axis from a direct line to the source (which is why a Mid/Side setup works well for this - the Mid microphone is always pointed directly at your source), thus retaining good direct focus on the subject while still getting sufficient direct imaging type stereo-ness. And also narrow because the A/B omni pair will be contributing plenty of the other kind of stereo-ness, meaning less stereo-ness is required from the "direct sound" focused pair for a good overall listening impression.

Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on June 25, 2018, 07:08:22 PM
^ I don't know if that's "how it's typically done" in the nature, ambience, and effects recording world or not.  Some will certainly feel that what I'm describing is not how it's typically done for live music recording either, but I'd argue this is basically what a AUD+SBD mix recording is achieving. 

To me this is a "bottom up" approach, starting from basic fundamental room acoustic and human hearing aspects and building a recording approach based upon those things with a target recording situation in mind- in which case the question becomes, What is most important and how do I go about translating that. Rather than working "top down" and starting from an presumed stereo pair of microphones in order to produce a stereo recording- in which case the question is a much higher level one, essentially- How do I setup a pair of microphones to make a stereo recording in such and such a situation.

Apologies if this is all a bit too philosophical, but it's what keeps me excited about recording as a gateway to listening.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: morst on June 25, 2018, 07:13:58 PM
This thread turned really interesting!

The Mid/Side control assumes the use of equal sensitivity mics and matched gain between channels.  In addition to the Mid/Side ratio you specify in whatever control you are using, any difference in sensitivity between the Mid and Side microphones and any difference in recording gains between the two channels also affect the Mid/Side ratio.  This is an additive "in addition to" thing (similar to the total gain being the sum of all gain stages- such as preamp gain plus recorder gain)
It must be hard to get perfect input levels with ganged-quads when attempting to work with Ambisonic formats.

Rather than working "top down" and starting from an presumed stereo pair of microphones in order to produce a stereo recording- in which case the question is a much higher level one, essentially- How do I setup a pair of microphones to make a stereo recording in such and such a situation.

Apologies if this is all a bit too philosophical, but it's what keeps me excited about recording as a gateway to listening.
When all you have is a pair of microphones, to mix a metaphor, everything looks like a nail!
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on June 26, 2018, 09:57:29 AM
It must be hard to get perfect input levels with ganged-quads when attempting to work with Ambisonic formats.

Yes, that's why the ability to "gang" or link the input gain controls on recorders used with ambisonic microphones becomes important. Ambisonics is multichannel Mid/Side.  Because there are typically four or more channels involved in the matrixing (3 at a bare minimum) rather than just two, it's critical to have microphone sensitivities and recording channel gains matched closely across all channels for the matrixing to work properly.

Unlike 2-channel Mid/Side where if the Mid and Side sensitivities and gains are not matched one can simply dial it in by ear ignoring the ratio number displayed in the Mid/Side controller, with ambisonics one needs to be careful to keep the gain the same at all times across all channels - preferably control linked, as that makes adjustment of all channels together easy if necessary.  The work-around for recorders which do not allow one to calibrate levels and gang the gain controls together is to set reasonable gains at the start of recording, not change gain during recording, record a short segment of the same test tone to each channel using the same gain settings as used during the recording, determine the level difference between the recorded test tones on the computer, and apply the differences in makeup gain across all channels prior to matrixing.   Much easier to make sure all gains are equal beforehand and remain that way during the recording.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: heathen on June 26, 2018, 10:54:50 AM
It must be hard to get perfect input levels with ganged-quads when attempting to work with Ambisonic formats.

Gutbucket pretty much covered this, but I'll add that I just look at whichever channel is getting the highest levels and adjust my levels according to that.  Note that I've got all four channels linked with the F8, so I'm still adjusting the gain equally for each channel.  Since the four capsules are oriented in different directions, though, it makes sense that one will have higher levels than the others.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: DSatz on June 27, 2018, 02:18:16 PM
just want to point out that heathen's reply is correct; for Ambisonic decoding to work, the GAIN of each recording channel must be exactly the same. Normally no effort should be made to make the levels equal; it's the gains that count. In any real-world recording the peak levels will almost certainly differ among the four channels, and that is as it should be.--best regards
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: relefunt on September 18, 2018, 11:36:53 PM
This is my favorite thread I’ve read on TS so far. It gives me something to think about each time I read it (about half a dozen times so far).

A sincere “thank you” to everyone who has contributed to it!
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: wlp on September 19, 2018, 07:50:54 PM
- 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.

Can anyone point me to where these add-on spheres can be found.  I'd like to try these for a pair of Senn 8020 mics.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on September 19, 2018, 11:38:39 PM
https://www.shapeways.com/product/VVM7XHA2G/acoustic-sphere-19mm-mic-40mm-diameter?optionId=61442338

Not sure though, if they will fit tightly with the mkh-8020s as their grille is irregular shaped. (I've got some 8020s myself.)
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: DSatz on September 20, 2018, 06:27:16 PM
... also, they're shown as fitting on Schoeps mikes which are 20 mm diameter, not 19.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: wlp on September 20, 2018, 08:08:32 PM
Apparently, they are offered multiple sizes.  I'm going to try a pair and will report back on the results.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: aaronji on September 21, 2018, 10:03:20 AM
^ DPA also offers these, the Acoustic Pressure Equalizers (https://www.dpamicrophones.com/accessories/acoustic-pressure-equalizer-ball-for-4006a), in three diameters.  The DPA mics are 19 mm, so I would imagine these would also fit other 19 mm mics.

I seem to recall Gutbucket also has a home-brewed solution using some type (Nerf?) of hard foam balls...
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on September 21, 2018, 11:03:55 AM
^ DPA also offers these, the Acoustic Pressure Equalizers (https://www.dpamicrophones.com/accessories/acoustic-pressure-equalizer-ball-for-4006a), in three diameters.  The DPA mics are 19 mm, so I would imagine these would also fit other 19 mm mics.

I seem to recall Gutbucket also has a home-brewed solution using some type (Nerf?) of hard foam balls...

If it's for both the d:dicate 4003 and d:dicate 4006A, its inner diameter might be only 16mm.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on September 21, 2018, 11:16:47 AM
Mine are appropriate for the miniature 4060 (5.4 mm dia) omnis I made and use them for, but I'd suggest either whichever Neumann/Schoeps/DPA spheres fit the Senns, or Shapeways 3D printed spheres made specifically to fit them.  The 3D printed stuff was not an option when I worked up the DIY Nerf hard-foam ball spheres or I would have explored that route. 

With the 3D printed option, I'd keep an eye/ear out for resonance of the plastic and any empty internal space within the sphere.  If that seems suspect, you might want to fill any internal void with something.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: beenjammin on September 21, 2018, 08:13:56 PM
This has been such a good thread, and I hope that it may continue to be of service to those looking for info on stereo configurations with the MK41 and other super/hyper cardioid mikes.

A quick update to my original post: I think I've settled on a Jecklin disk with my MK2s. This gives me the stereo separation I initially sought. As far as reach, I took a cue from photographers with wide angle lens and focus with my feet, placing the mikes closer to the source.

In fact, I've been running the Jecklin disk handheld! While I have to be very careful, I've found that if I'm quiet enough I can get very good results. This has an added benefit. Instead of setting the mikes on a stand and letting them run for hours, I now capture what I want and edit on the go. If some sound interferes with the recording, I end the take and move on. I've never had so much fun recording.

There are two drawbacks. One, the Jecklin disk gets heavy, and after about 12 minutes, my arm needs a break. Hopefully, I'll build up more muscle mass. Two, I look like a madman. People notice me running around and seem to have no clue what the hell I'm doing. I figure it's only a matter of time till someone calls the authorities.

This summer I was up on Mt. Hood in Oregon, trying to capture Bumble Bees and a pair of wildflower hikers thought I was tracking mountain lions!  :guitarist: 
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: achalsey on September 22, 2018, 12:51:38 AM
^ DIY J-Disk, or purchased?  I'm not sure how you're holding the disk, but a monopod would definitely be your friend.  I don't know anything about them, but I do trust the internet.  Maybe someone else can chime in on that front.

https://www.adorama.com/alc/best-monopods-for-cameras
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: beenjammin on September 22, 2018, 10:31:35 AM
I picked up the Josephson disk and run it with a hand grip. It was expensive (~300) but much cheaper than a new set of caps. I have a light stand with me at all times, but monopad is a very good idea. One nice thing about running everything handled is the ability to move through thick brush with (relative) ease.

Incidentally, it appears that the Jecklin disk requires a slight hi frequency lift to compensate for the acoustic baffle. I guess one of the MK2 variants -- h, s, x -- would be ideal, but I read a thread on Gearslutz where someone claimed to have it on authority of a Schoeps engineer that the right in-software filtering could render any two variants acoustically identical. I've been playing around with a simple high shelf filter with good results.

In any case, this summer's recording has made me a Jecklin convert. Save the lovely Schoeps KFM omni sphere, I can't think of anything better for my purposes.

Here's a link to an example made by someone in the UK of the KFM sphere:

https://aporee.org/maps/?loc=14813&m=satellite
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: DSatz on September 23, 2018, 09:33:34 AM
beenjammin, it's not primarily the Jecklin disk itself that calls for a mild high frequency lift in the microphone's free-field response; it's the miking distance.

Practical, professional-quality omnidirectional microphones aren't omnidirectional at high frequencies because of their physical size. And omnidirectional microphones at normal, audience-type miking distances pick up only a relatively small proportion of direct sound as compared with reflected sound. Before reaching a microphone that's not pretty close to the direct sound sources, reflected sound has almost always undergone absorption that affects the high frequencies more than low or mid frequencies.

Thus if you choose a capsule like the Schoeps MK 2 for recording at a distance in a reverberant space, you will get a dark sound; its super-flat on-axis curve (how flat can a curve be, and still be called a curve?) doesn't apply when the predominant sound energy is coming from off-axis.

I've attached several graphs to this message. One shows the approximate difference between the on-axis response of a small (Schoeps-sized) omni and the general, integrated response of the same capsule to sound arriving from random directions in three-dimensional space (a/k/a the "diffuse-field" response). Omnidirectional microphones have more of this difference than any other type except shotgun microphones. (Conclusion: Shotgun microphones designed for placement fairly close to the direct sound source aren't a good bet for more distant recording in reverberant environments.) (Oh--that's every shotgun microphone ever made by anyone.) (Oops.)

But yeah, in most Jecklin arrangements, the capsules don't face the direct sound sources. So that's a factor, too.

> I guess one of the MK2 variants -- h, s, x -- would be ideal, but I read a thread on Gearslutz where someone claimed to have it on authority of a Schoeps engineer that the right in-software filtering could render any two variants acoustically identical.

The MK 2 S would be my suggestion. And yes, all four of Schoeps' omni capsules have essentially identical polar response (see attached graphs) and all other parameters, except their high-frequency response. Thus if you equalize them appropriately, they become interchangeable with one another both on- and off-axis. That's not "inside information" nor is it a situation unique to Schoeps.

(note that in the attached graphs, the old MK 3 is still called by that name; it was renamed to "MK 2 XS" a few years ago, but it's the same capsule. It has approximately flat response when placed in a diffuse sound field, i.e. where rather little of the incoming sound is direct/on-axis. This makes it a special-purpose item in terms of modern, stereophonic recording, but it still has some applications today.)
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on September 24, 2018, 12:15:50 PM
Incidentally, it appears that the Jecklin disk requires a slight hi frequency lift to compensate for the acoustic baffle.

beenjammin, it's not primarily the Jecklin disk itself that calls for a mild high frequency lift in the microphone's free-field response; it's the miking distance.

True that miking distance is the primary factor by far, and I certainly do not mean to contradict DSatz, yet from personal experience I've found there is truth to the statement about Jecklin disk recordings benefiting from more high frequency lift than a recording made without the baffle using the same omnis from the same recording location.  I know other tapers have reached the same conclusion.

I'm not certain exactly why that seems to be the case, but I suspect it might have to do with one of two things, perhaps both in combination-
1) Compared to the direct arriving sound, the reverberant pickup using a Jecklin disk is somewhat darker than when not using the disk.  The directionality imparted by the disk off-axis is not constant with frequency.  The baffle is not absorbing/blocking any sound at the lowest frequencies, yet does so increasingly as frequency increases, and because of that, the reverberant pickup becomes darker in comparison to the direct sound.  This makes the overall balance of the recording (both direct and reverberant combined) somewhat darker without any EQ compensation applied.
2) The presence of the baffle reduces phase interaction between the two channels at mid and high frequencies, and perhaps the comb-filtering phasiness without a baffle attenuating it translates as brighter sounding. 

Would very much like to hear your thoughts on this David.  I hear this frequency balance effect clearly, but perhaps I'm attributing it to the wrong things.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: DSatz on September 24, 2018, 06:06:23 PM
No, Mr. Bucket, actually what you say makes complete sense to me. The disk is too small to act as a baffle except at upper-mid frequencies and higher. At any rate, my main point was that microphones with the same polar response (as a function of frequency) can generally be equalized to sound like one another.

Early in my recording career I upgraded from AKG C 451 omnis to Neumann omnis (KM 83). The KM 83 were like the KM 183 of today--fully diffuse-field equalized, like the MK 3 (oops, MK 2 XS nowadays) in the Schoeps line. I thought that my recordings with them sounded wonderful in the bass and midrange, but icky on top--"metallic" sounding and uncomfortable to listen to, like the way aluminum foil tastes sometimes if you accidentally bite into it. But I didn't want to move my mikes farther back, because then they would drown in reverb. So I got a pair of cardioid capsules for the KM 80-series bodies, and I don't think I ever used the omni capsules again.

Fast forward to 25 years later, when I understood this all better. I dug up some of the recordings I'd made with the KM 83s and simply by reducing the high frequencies a few dB, equalized them to sound better than I'd ever realized they could. So I know first-hand that this can really happen.

--best regards
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on September 25, 2018, 09:16:14 AM
That biting aluminum foil simile is so apt.  Such an excellent descriptive!

Thanks and best to you.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on September 28, 2018, 03:09:19 PM
Mine are appropriate for the miniature 4060 (5.4 mm dia) omnis I made and use them for, but I'd suggest either whichever Neumann/Schoeps/DPA spheres fit the Senns, or Shapeways 3D printed spheres made specifically to fit them.  The 3D printed stuff was not an option when I worked up the DIY Nerf hard-foam ball spheres or I would have explored that route. 

With the 3D printed option, I'd keep an eye/ear out for resonance of the plastic and any empty internal space within the sphere.  If that seems suspect, you might want to fill any internal void with something.

Got my Shapeways 3D printed spheres for the MKH-8020's today. In fact there is some empty internal space within the sphere - apart from the 3-D printed fins ("grasping mechanism") on the inside.
Other than this, build quality appears to be pretty solid.

Tempted to try them out in the field, although my next open recording opportunity (next Sunday) will be on-stage - and the spheres are meant to be used further back in the room.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on September 28, 2018, 03:46:30 PM
They look nice.  How do they fit?

[snip] the spheres are meant to be used further back in the room.

The spheres help from further back by increasing on-axis sensitivity in the upper presence range versus the off-axis response, and are appropriate anywhere that attribute is desirable.  It's more about that on-axis/off-axis difference than the difference in overall integrated frequency response, which can useful but can be EQ compensated for just like compensating MK3 response to that of MK2 or vice versa.  The on/axis off/axis difference cannot be EQ compensated for afterwards.

Consider that the original Neumann M50 (and later models) upon which all these spherical attachments are descendants is primarily used for main microphones positioned over the orchestra conductor's head- a position not significantly more distant than a stage-lip taper position in some cases.  The acoustic situation is different however, with an unamplified band (orchestra) in a large hall and good sounding, relatively long-decay reverberation time.

With all that in mind, the main difference you are likely to hear with and without the spheres after optimally adjusting EQ of both for good direct-sound from the band, is the difference in timbre of those sound components which are not arriving directly on-axis - the room reverberation, audience reaction, and perhaps off-axis PA bleed.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on September 30, 2018, 03:26:32 PM
They look nice.  How do they fit?

Sorry for not replying earlier. The mics were still at my flat while the spheres were delivered to my house.

They fit really well. It took me a while to figure out that you must screw in the mics clockwise (because of the internal grasping mechanism).
This might lead to cosmetic issues in the long run if the labeling isn't abrasion-proof. (Not an issue with these Sennheisers.)
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on October 01, 2018, 09:28:54 AM
Fit appears appropriately flush at the grid/sphere interface. 

Please post your thoughts and impressions once you get the opportunity to use them a few times.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: JimmieC on October 01, 2018, 10:53:54 AM
I like the idea of these spheres or port covers to alter your microphones.  I see they are using these spheres on omni microphones.  I understand they modification of your microphone's on-axis and off-axis frequency responses and direction-to-reverberation ratio.  Can I ask 3 stupid questions that might have already been answered but did see it.  Does it make an omni into a cardioid (or preferably a hyper / super cardioid) pattern?  Can they be used on cardioid mics?  Can port covers make a cardioid into a super cardioid with out buying a new set of capsules? 

In realtime, I wish I could bump the mids and just a slight in the high end but can't do anything about the direction-to-reverberation ratio without doing MS or maybe some spheres / port covers.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on October 01, 2018, 11:19:51 AM
The sphere attachments only work with pressure-omnis.  They are not a "port covers" and do not work with any pressure-differential mode microphones which incorporate rear/side vents.  They do not apply to cardioids, supercards, figure-8's, or electronically-switchable-pattern microphones.  Best to think of them as emphasising the slight inherent directionality most omnis already have at high frequencies.

It will not turn an omni into a cardioid or supercardioid as such, but does push the pattern toward something cardioid/supercardioid shaped at high frequencies only.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: if_then_else on October 01, 2018, 01:23:56 PM
Fit appears appropriately flush at the grid/sphere interface. 

Please post your thoughts and impressions once you get the opportunity to use them a few times.

I'm going to open tape Part Chimp next Sunday. But, honestly, I have some serious doubts that you'd notice
such subtle differences at their deafening volume. I'll try out the spheres anyway and will let you know how it went.

I'd love to run them at a singer-songwriter / "dark folk" show in France in November but haven't heard back from the artist yet.

Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: wlp on October 01, 2018, 05:07:05 PM
The Shapeway spheres came a few days ago and, after a little adjustment (sandpaper), they fit the 8020's snug without marring the finish.

Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on October 01, 2018, 05:50:24 PM
^ Not flush enough. Push the ball less far onto the microphone, such that only the mesh grid sticks out past the front of the ball, and not the solid portion of the microphone body.
Title: Comparison samples- 60cm spaced omnis with and without sphere attachments
Post by: Gutbucket on October 22, 2018, 03:49:20 PM
I recently came across a website specializing in classical recording, which has generously made available various comparative sample recordings for download.  The methodology seems well-controlled, making these comparisons useful for us.

   The Research on Classical Music Recording - for the future of music production and recording
   Nagoya University of the Arts, Kazuya Nagae
   http://kazuyanagae.com/ (http://kazuyanagae.com/)


Of the various comparisons linked there, one is of pairs of 60cm spaced DPA 4006 omnis with and without the DPA 50mm diameter APE sphere attachments installed. Listen for yourself and hear the somewhat subtle but certainly audible effect imparted by the spheres here-
http://kazuyanagae.com/20110930windorch/index.html (http://kazuyanagae.com/20110930windorch/index.html)


Also hear the comparison of 30cm, 60cm, and 100cm omni spacing without the sphere attachments-
http://kazuyanagae.com/20110420orch/index.html (http://kazuyanagae.com/20110420orch/index.html)

I've yet to explore the other comparisons.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: Gutbucket on January 07, 2019, 09:41:44 AM
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?

Circling back to the original post above inquiring about appropriate configurations for a stereo pair of MK41 supercardioids, this link is to the Improved PAS technique thread- https://taperssection.com/index.php?topic=167549.msg2087409#msg2087409 (Improved PAS setups - better imaging & higher direct/reverberant-sound ratio)

The tables in the first post there suggests the appropriate spacing between a pair of microphones given the angle between them, in the special case where the two microphones are pointed directly at what the recordist wishes to be the outer edges of the reproduced stereo image.  The first simple table covers a pair of cardioid pattern microphones only.  The second larger table extends to patterns other than cardioid as well.  To use the second table for a pair of MK41, first determine the appropriate angle between microphones by aming each at either side of the "sound stage" you wish to reproduce between the speakers (angling them less widely to focus more narrowly, and vice-versa), then determining the appropriate spacing to use between the two microphones by finding that angle in the first column and following the row over to the supercardioid column where the spacing between microphones is indicated.

This Point At Stacks microphone technique is intended to simplify setup while maximizing pickup of direct sound as much as possible from a given recording location.  Although primarily intended for PA taping, it should also help in clearly capturing a particular source of interest while retaining good stereo reproduction width for the type of recording you describe.  The total range of the various angle/spacing combinations covered by the table includes and extends beyond the standard near-spaced conventions of ORTF, NOS, DIN, etc.

Hope this helps.
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: noahbickart on January 07, 2019, 10:08:50 AM
People might be interested in these recent Phish mk41v MSG recordings, using the PAS (stereo zoom) method:

12/29:
mp3: https://drive.google.com/open?id=1ZmIc_GUYn9ku4P6OHzIns8EPPKnCmcs8
16bit: http://bt.etree.org/details.php?torrentId=603517
24bit: http://bt.etree.org/details.php?torrentId=603514

12/30:
mp3: https://drive.google.com/drive/folders/1dXKjakaF244pQ6WNEeXF8ZCbYRGvrLpZ?usp=sharing
16bit: http://bt.etree.org/details.php?torrentId=603553
24bit: http://bt.etree.org/details.php?torrentId=603554

12/31
mp3: https://drive.google.com/open?id=10WCdN3wT5oII0CESqQG2RWuFHz6N-pgT
flac 16: http://bt.etree.org/details.php?torrentId=603586
flac 24: http://bt.etree.org/details.php?torrentId=603585
Title: Re: Stereo Technique with MK41 or other super-cardioid Microphones
Post by: kuba e on January 07, 2019, 11:29:16 AM
Noah, thanks for recordings.

I recently came across a website specializing in classical recording, which has generously made available various comparative sample recordings for download.  The methodology seems well-controlled, making these comparisons useful for us.

   The Research on Classical Music Recording - for the future of music production and recording
   Nagoya University of the Arts, Kazuya Nagae
   http://kazuyanagae.com/ (http://kazuyanagae.com/)


Of the various comparisons linked there, one is of pairs of 60cm spaced DPA 4006 omnis with and without the DPA 50mm diameter APE sphere attachments installed. Listen for yourself and hear the somewhat subtle but certainly audible effect imparted by the spheres here-
http://kazuyanagae.com/20110930windorch/index.html (http://kazuyanagae.com/20110930windorch/index.html)


Also hear the comparison of 30cm, 60cm, and 100cm omni spacing without the sphere attachments-
http://kazuyanagae.com/20110420orch/index.html (http://kazuyanagae.com/20110420orch/index.html)

I've yet to explore the other comparisons.

Gutbucket, thanks too. There are great material to listen for comparison. With and without APE sphere and differently spaced omni recordings are very interesting.