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Gear / Technical Help => Microphones & Setup => Topic started by: digifish_music on February 10, 2009, 06:46:12 AM
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Slow but captivating
http://www.youtube.com/watch?v=9Quwx1GEaRc
:)
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Thanks for the link.
I got all excited and self-congratulatory at 8:10 and 8:20 to see them rigging up a fancy Schoeps version of my quad-eye rig. 8)
(http://taperssection.com/index.php?action=dlattach;topic=96009.0;attach=88607;image)
(http://taperssection.com/index.php?action=dlattach;topic=96009.0;attach=88605;image)
(http://taperssection.com/index.php?action=dlattach;topic=96009.0;attach=88617;image)
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SD fluffing here: at 1:04 we see an SD 722. However, there are no input cables. Hopefully this is not a sly dig on the part of Schoeps. 8)
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Thanks for the link.
I got all excited and self-congratulatory at 8:10 and 8:20 to see them rigging up a fancy Schoeps version of my quad-eye rig. 8)
I thought that looked familiar :)
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Did you note the omni towards the end in the clear plastic ball, a la Neumann M50? DPA uses these spheres, too, as do others to focus the omni and get the best of omni and card, it says here. At a distance it can be used to focus the omni on what is in front and attenuate what is not.
Lee has done work with this, too.
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I got all excited and self-congratulatory at 8:10 and 8:20 to see them rigging up a fancy Schoeps version of my quad-eye rig. 8)
Looks interesting. Is there any further info available on the web?
Ralf
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I've posted info on what I've been doing in the Oddball Mic Techniques thread (http://taperssection.com/index.php/topic,96009.msg1279052.html#msg1279052). Details on the surround rig pictured above and external links to info on sphere baffle attachments for omnis is on page 6 of that thread (http://taperssection.com/index.php/topic,96009.msg1517359.html#msg1517359). More info and photos of the baffles in a stereo A-B setup is earlier in the thread.
The root of the idea dates back to the classic Decca tree rig using three Neumann M50 acrylic sphere omnis. I found a lot of useful information about the APE spheres at the old DPA site but the technical article on what they do, how they work and the corresponding measurements isn't on their new site yet.
I haven't seen any info on a Schoeps version of the sphere baffles or surround tree until seeing the clip above. If anyone finds additional information on that please let me know.
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One reason I kept watching this video after the start, was that Jorg Wuttke mentioned the importance of factors in a good recording...
1. Performance
2. Room
3. Mic recording technique
4. Mic
...that got a big tick from me :)
digifish
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The man knows.
Big tick on those priorities.
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The man knows.
Big tick on those priorities.
Performance transcends the medium every time.
I took a vocalist I record down to the local music shop, she was looking for a gigging mixer with built in FX, and I remember we needed to demo it somewhere, so they shuffled us out into the hire section, like a big warehouse + loading bay, full of guys packing/unpacking battered black boxes full of PA/stage gear for hire.
In the corner on a bench we were shown a battered old PA system they use to test gear before it goes out/in, quietly fizzing/humming. We plugged the mixer into it and grabbed an old battered SM58 mic laying on the bench, selected a reverb preset and she started to sing an A capella. The whole place ground to a standstill as everyone was transfixed at this beautiful voice for about 30 seconds no-one moved, when she was finished, silence then applause.
technically, the sound through the PA was truly crap, but the performance was spine tingling...
digifish
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Details on the surround rig pictured above and external links to info on sphere baffle attachments for omnis is on page 6 of that thread (http://taperssection.com/index.php/topic,96009.msg1517359.html#msg1517359).
From a quick look at the link, this looks most interesting. You wouldn't happen to have a surround sound example recorded with this set-up online somewhere, by any chance?
Ralf
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Ralf,
Not yet. I've concentrated solely on the capture side so far and I'm just beginning to look into post processing some of these recordings. I've used two stereo recorders for the 4 channels and need to align and sync the tracks and put them into some sort of multichannel delivery format, perhaps DTS encoded or DVD-A files. Currently for checking surround playback I sync playback manually on the recorders. A 4-channel recorder and a multi-channel DAC for computer playback so I can start editing are next. I'll try to remember to let you know when I get something together.
~Lee
Digifish,
Although the quality of sound we record and playback today is far beyond that of the cheap cassette deck and Sony headphones I listened to when I fell deeply into the mystery of music as a teenager, it was the quality of the music itself - the performance, not the fidelity that captured me forever. I'm still chasing that dragon and still get that same spine tingling sensation when the music is transcendent, regardless of the sound quality. Recording is just a tool to deliver that experience. It's like an instrument, essentially silent until someone plays it.
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Gutbucket, the translucent sphere shown in the video is not a Schoeps product, but Schoeps has offered accessory spheres (40 mm outside diameter) for their pressure capsules for many years now. The MK 2 S is especially recommended for "Decca Tree"-style recording.
There is a set of Beethoven symphony CDs on the market in which some of the symphonies were recorded with three Neumann M 50 microphones and the rest with three Schoeps CMC 52 S microphones. If you don't already know which ones are which, it's hard to hear the difference even on a direct comparison--and if you didn't already know that two different sets of microphones were used, you wouldn't guess it. I say this as someone who has actually recorded with real M 50s, which are amazing microphones. They can maintain sonic focus at an almost unbelievable distance in a reverberant environment.
Below are a pair of quick photos of a KA 40 accessory sphere on an MK 2 S on a Colette cable. I've used this type of setup a few times for classical stereo recording. The spheres can also be placed on the complete microphone, of course (without an active cable), or on a capsule using an active tube such as the RC 700, or an SKC -- gooseneck.
--best regards
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Schoeps has offered accessory spheres (40 mm outside diameter) for their pressure capsules for many years now.
Interesting, pressure = omni I assume?, what are the spheres made from?
digifish
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Typically hard plastic- clear acrylic, black Delrin. For omni mics only, they'd block the rear ports of a directional.
DSatz,
Could you share you're thoughts about which situations and in which way you'd choose to use this type of mic?
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Gutbucket, you've got it right as far as the material goes (though there is a soft inner lining to be kind to the capsule), and also the very important point that this technique is usable only with sealed = pressure transducer = omnidirectional capsules.
The main effect of the sphere is to create a presence boost in front of the capsule and to narrow (but not by a lot) its polar pattern at mid-high frequencies. This allows you to back away from the sound sources somewhat, and to pick up a (possibly) improved blend as a result, plus more reverberation at low and mid-low frequencies without losing "focus."
The original application for which this type of microphone was designed (by Dr. Herbert Grosskopf at the NWDR in Germany in the late 1940s) was single-mike pickup of an entire orchestra in a concert hall. This was, of course, in the mono-and-vacuum-tube era. If you're picking up an entire orchestra with a single mike, that mike has to be quite some distance away from the orchestra or else the balance will favor the instruments in the front and center too much. But Grosskopf wanted the full low-frequency response that can only be obtained from a pressure capsule, so he came up with this approach which allows the microphone to be placed farther back.
This, by the way, also explains why microphones such as the Neumann KM 183 have such a pronounced elevation at high frequencies--they're successors to the "diffuse-field equalized" microphones that were used for single-microphone pickup in reverberant spaces in the mono era. Nowadays we mike in stereo and somewhat more closely, so omni microphones with less high-frequency emphasis are generally favored.
--best regards
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For omni mics only, they'd block the rear ports of a directional.
Yes ... actually I was wondering if that would convert a card into an omni?
digifish
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It would convert a cardioid into an omni with terrible frequency response and an inordinate sensitivity to wind and breath and handling noise. The diaphragm tension and the air volume of the internal acoustical chambers behind the backplate of a cardioid are totally inappropriate for an omnidirectional microphone.
If all it took to make a usable two-pattern capsule was putting an acoustically opaque collar around a the rear sound inlets of a cardioid, that's how everyone would do it.
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If all it took to make a usable two-pattern capsule was putting an acoustically opaque collar around a the rear sound inlets of a cardioid, that's how everyone would do it.
Mom! DSatz is being mean to me again!!! :P
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> Mom! DSatz is being mean to me again!!!
Sorry--that probably was a little blunt. But I wanted to drive home the point that these sphere attachments--or putting duct tape over the rear sound inlets for that matter--aren't the easy way to a two-pattern capsule.
Schoeps as a company turned 60 years old this year, and one of my projects has been to help them prepare for a historical retrospective. In the process I researched the company's inventions, and read as many of their patent applications as I could track down. Their 1950s patent application for a two-pattern capsule using a single membrane features a cross-sectional drawing which I've attached below. It's not nearly as tricky as their three-pattern capsule, but its internal features do need to be designed specifically for two-pattern operation.
It's interesting to note that in the years since this patent expired, only one other manufacturer (Shure) has successfully implemented this approach. It's the only known way to make a switchable-pattern capsule with (a) an omni setting that has full low-frequency response and no proximity effect or sensitivity to wind, breath and handling noise, plus (b) a cardioid setting that remains a true cardioid even at the lowest frequencies.
--best regards
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Does that approach use some sort of mechanism to adjust diaphragm tension as well as opening an acoustic labyrinth to the back side of the diaphragm for the cardioid mode, or is there some other clever scheme that gets around the fundamental diaphragm tension difference issue?
Having sifted through the bizarre lexicon of patent speak searching for the real workings of things rarely described elsewhere in conceptual detail, reviewing all those Schoeps patents sounds both intriguing and utterly exhausting. You'll surely end up one of the more knowledgeable native English speaking experts on that rich history of innovation. I envy the conceptual insights while I'm overwhelmed just imagining the sheer quantity of effort required to sift the details. I really look forward to seeing that 60 year historical retrospective.
It may seem i constantly post accolades for your clear, informative posts, but thanks again for lending a unique perspective and your outstanding contribution to educating us amateur recordistapers.
~Lee
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Gutbucket, thanks for the kind words, but my only formal education is in classical music; I don't know enough physics to understand everything that is said in these patent applications. The distinction between electrostatic charge and voltage, for example, has me stumped these days; in a condenser microphone capsule, as the membrane vibrates, the charge remains constant while the voltage varies, and that varying voltage is where the signal comes from. At the same time the membrane is being charged from a constant voltage source--though there's a very large resistance in between which prevents that voltage from canceling out those variations in the short term (and thus smoothing the audio signal into nonexistence). I can say the words and work some of the formulas, but what do they really say and how would you build on that understanding?
What has helped me the most has been finding the occasional journal article in which someone who does understand the physics has broken it down for normal people. Also I have some friends I can call and ask, and fortunately, one of them is Jörg Wuttke--the guy in the video that started this whole thread. I've translated his work for many years now, and each time I work on a major project with him (as I'm doing now--a paper that he'll be delivering in English at the Munich AES), as part of my "payment" I throw a few questions at him.
Jörg is officially retired now, though he still consults for Schoeps and still does his educational speaking and writing (in three languages). The two guys who now have the top positions at Schoeps are also very friendly humans, and have been quite helpful to my continuing education. They're Dr. Helmut Wittek--who, by the way, does a lot of live recording himself, and would be very much at home in some of the discussions on this forum--and Christian Langen, their director of new product development. You can see both of them in other videos that are on YouTube.
Anyway, no--the pattern-change mechanism in the Schoeps MK 5 and MK 6 doesn't adjust the membrane tension; I doubt that such a mechanism could ever be precise and robust enough to do so reliably, especially over a span of decades. The first product built according to the design shown in this patent was the M 934 two-pattern capsule of the M 221 series (later renamed the MK 5 when it reached the "C" revision level, with a Mylar membrane and a new, recessed actuator lever design that is the familiar one nowadays). Quite a few of those capsules have been in use for 40 to 50 years now without an overhaul, though I bet some of them could use a good cleaning by now.
--best regards