DSatz

Constantin, the earlier Schoeps digital mike amp--introduced nearly twenty years ago--was the CMD 2. It, too, was an AES42 device, but it supported only mode 1, in which the microphone is self-clocking, which means that you can't sync your recording to a camera or house clock, or run multiple microphones, unless your recorder has sampling rate conversion built in.

The CMD 42 is indeed a complete redesign--as it should be, since the components available for a project like this are worlds better than they were twenty or even ten years ago.

--I need to disclose occasionally that I've done translating and editorial consulting for Schoeps for many years, and I'm subject to the human tendency toward bias. (Also equalization.)

Yes, but a FET impedance transformer stage is primarily a current amplifier; the voltage coming from the capsule is generally quite sufficient. Analog microphones have to drive loads as low as 600Ω sometimes; the IEC standard says 1 kΩ or greater, but some preamps don't maintain that at the frequency extremes--and you want to avoid a frequency-selective voltage divider effect, which necessitates almost a mini-power amplifier stage at the output of the mike.

But there's no such requirement if you're going from the impedance transformer directly into a converter; you can generally eliminate a circuit stage or two, and optimize your (internal) operating levels and impedances for best dynamic range. Neumann used a ganged, gain-ranging converter arrangement, and with some components that have been developed more recently, the input noise of the converter can be less of a problem to begin with. In the end the equivalent noise level of the combination can be within a dB or so of the corresponding analog microphone. Neumann achieved that in their AES42 microphones as well (they are certainly no slouches).

Schoeps had the CMD 42 under development well before Neumann / Sennheiser backed out. They felt that there is some range of customers who could be helped by this technology, and its development wasn't taking away too many resources from their other work, and was inherently interesting, so they continued. It was also affected by the pandemic and the owner's and managers' decision not to let people go even though new orders plummeted for a while (since then, the difference has been more than made up for).

They haven't gambled the whole farm on this one project, in other words. They'll do fine with their existing analog product line, which they've also been developing further. If manufacturers of mixers, recorders, and outboard gear choose now to offer more support for AES42, there'll be more of an "ecosystem"; if not, not. But there's no way that those other manufacturers could make digital microphones of a quality that people would want to use, so Schoeps has done their part--a big part in principle and potentially, in practice--and now we'll see.

Before the topic changes completely, let me just chime in to agree with Constantin that AES42 is definitely more than just a passive interface for receiving digital audio signals. Unlike AES3 it has a control channel that runs from the interface to the microphone(s) (along the same set of wires, of course), and quite a few essential commands are predefined in the standard, such that all AES42-compatible microphones should implement them. Some other commands are "defined but optional." And there's also a range of command codes available for manufacturers to define for themselves however they want, so that unique features can be offered.

What you can do in Mode 2 that you can't do in Mode 1: [a] record synchronously with any given timing signals, such as a master clock, without using sampling rate converters [b] run multiple microphones without sampling rate converters. In Mode 1 each mike is independently self-clocking, and no two are ever exactly alike.

Um, no, I meant https://www.youtube.com/watch?v=2st7KzoEHlo starting at 24:01. This came up last August on an amateur audio forum that I sometimes participate in ("Tapers Section"), where someone had watched this video but perhaps didn't understand the German being spoken, and thought that Wittek was recommending to set analog preamps to low gain levels such as 20 dB for best noise performance, which definitely isn't right. Here's what I posted back then:

> [T]he topic from about 24:00 to about 30:00 in the recorded talk is dynamic range, which takes into account both the noise floor and the maximum SPL of the signal chain. He's very concerned to compare apples with apples: the digital microphone with the analog microphone PLUS the preamp that you have to use with it [whether standalone or built into a mixer or recorder].

> As he says (ca. 26:30), the CMD 42 isn't limited by having to pump out high voltages (more electrical power) at higher SPLs, so its maximum SPL is a few dB higher than that of the CMC 6. But when you bring an analog mike preamp into the picture (ca. 27:15), the clipping point of its output becomes a much more serious limiting factor when you get near the maximum SPL of the microphone. In the slide at the point that you mentioned, he's saying (around 28:20) that you would need to limit the gain on your preamp to about 15 - 20 dB in order to avoid this overload at the maximum SPL.

> He's definitely not saying that this is an optimal setting--on the contrary! His whole point is that analog preamps typically have lower input noise than the microphone's output noise only when set to higher gain levels than that, such as 30 - 35 dB. (This was shown in earlier slides, ca. 25:15 - 26:00.) Thus there exists no one gain setting for a typical analog preamp that both accommodates the maximum SPL of the microphone without clipping, and simultaneously offers the lowest noise for the quietest sounds that the microphone can pick up. If you need to record both at the very highest and the very lowest SPLs without touching any gain settings in between, the digital microphone offers a definite advantage as compared with the analog microphone--given that typical analog mike preamps can't put out 10, 20, 30 or more Volts (not that you really would want such levels to occur in practice).

> But then he goes on to say two things. (ca. 28:55) "With suitable operation of the preamp, I can obtain performance from the analog system that is exactly as good, or nearly as good, as that of the digital microphone. But I must operate it in a suitable way; I must really set exactly the gain level that suits my application exactly." Secondly, (ca. 29:50) combination analog mike preamps and A/D converters exist that use multiple analog gain stages and gain ranging--and he says that such equipment can produce results that are very nearly equivalent to digital microphones.

--best regards

There are real-world situations in which a digital microphone can offer an audibly lower noise floor than a comparable analog microphone. For years I used to think that digital microphones were just a rearrangement/refactoring of the same set of components (capsule, preamp, a/d converter) as in a digital recording setup with analog mikes, and yes, that is true for the most part.

But the hitch is analog mike preamps (whether outboard or part of a mixer or recorder) and their noise levels and headroom in relation to their gain settings. Mike preamps, contrary to what some people apparently assume, are nearly all at their quietest when set to the upper range of their gain settings. If the sounds that you're recording include very high SPLs (even for brief intervals), you can't leave the gain of the preamp (or analog recorder or mixer input) set very high, or you'll clip the analog electronics. As a result, you have to set the gain for the loudest sound that you expect to pick up, which raises the noise floor for the quieter parts of whatever you're recording, compared to what that noise floor would have been at higher gain settings. Sometimes this raises the preamp's noise floor above that of the microphone or the recording environment. And that's a compromise that you don't have to make with digital microphones.

As a result, every now and then people with real, professional experience find to their astonishment that digital microphones are quieter or even (as some have said) much quieter in certain recording scenarios than the comparable analog microphones had been for them before. I used to think those people were tripping--but now I realize that they could very well be describing their experience accurately, though perhaps not understanding that no, the microphones themselves aren't any quieter; it's the benefit of working without the occasional limitations of analog preamps. The effect isn't extremely common, but I think it's 100% real when it occurs.

Does that explanation help? There's a video in German that Helmut Wittek from Schoeps posted on YouTube that goes into this; I could provide a breakdown of it in English if anybody wants.

--best regards

Hello. The capsule in the Schoeps CMIT 5 and "MiniCMIT" is absolutely one and the same (including the backplate)--it's not two different capsules with the same outward dimensions. Capsule assemblies are generally made without knowing which microphone they will go into. The shorter microphone has a shorter amplifier with no switches or LEDs.

The fixed low-cut filters of the two types are a bit different (CMIT 5 = 3-pole, 80 Hz while MiniCMIT = 4-pole, 70 Hz) but the sensitivity and gain are the same. On a careful, direct comparison with low-frequency-heavy program material, given suitably loud playback I imagine that a difference could be heard--but that's hardly a typical use case. Films and videos have reportedly been made in which the sound recordist switched between the two types of microphone with no one hearing any difference, while to my knowledge no contrary outcome has been reported so far.

Glenn, your hypothetical situation seems to assume an entirely undithered a/d converter. In a properly dithered system none of your conclusions apply. Very low-level signals may be close to the noise floor, but they won't suffer any distortion due to the small number of bits that are actively flipping in any given time span.

--best regards

Especially where there is cable-borne electrical noise from RF, consider a CMC 1 L amplifier + MK 41 capsule as an alternative to a CCM. The combination is only 1 mm longer and the built-in protection against RF entering the CMC 1 via the cable is significantly more advanced than that in the CCM (or even the CMC 6). The total price is actually a bit less, and if you need a different capsule some day, you can get it without paying twice for the electronics of the mike, plus you can interpose a low-cut filter such as the CUT 60 or other active accessories when needed.

The CMC 1 also uses significantly less operating current than the CCM and on 48-Volt phantom, has 4 dB higher maximum SPL before reaching the point of distortion.

I guess to some people the unitary construction of the CCM is conceptually simple, so they may assume that it's better shielded, but actually the reverse is true especially where RF is present on the signal cable.

Just wanted to mention that it is the absolutely identical capsule. The capsules are in fact made without knowing which model of microphone they will become part of.

--And on that topic, the company has put a lot of work during the past two years into making the capsules of their shotgun mikes more resistant to the effects of high humidity. With no public announcement they introduced a new generation of capsules (same acoustic design/performance/sound/specs as before) and watched as complaints decreased. There's now an upgrade program in place if you want to have a new capsule installed in your CMIT 5 or MiniCMIT -- see the fourth item in the "Service FAQ" on https://schoeps.de/en/support-service/service.html (English) or https://schoeps.de/support-service/service.html (German). (That text is preliminary and may change somewhat by the end of this week, but the essentials are there.)

They've also posted some advice on their Web site about how to avoid the problems in general, though it's fairly common-sensical and will be well known to many people here ( https://schoeps.de/en/knowledge/knowledge-base/schoeps-microphones-in-extreme-weather-conditions.html in English, https://schoeps.de/wissen/knowledge-base/schoeps-mikrofone-bei-extremen-wetterbedingungen.html in German).

--best regards

Hi. The B 5 D was invented for use on the singers' microphones at an outdoor concert of The Three Tenors. Schoeps' products that start with "B" ("Besprechungsschutz" in German) are "close talking guards" or "pop screens". They're designed for  when moving air is expected to arrive mainly in front of the capsule; that's where they have most of their protective effect. The "D" stands for Decca, who were planning to record the concert for CD and DVD release, and came to Schoeps asking for improved protection with the least possible effect on the sound quality.

The products that Schoeps designs as windscreens have "W" ("Windschutz") at the start of their names. They enclose a larger volume of air and/or they keep the moving air equidistant from all sides of the capsule. And as a result they have much better protection for the rear sound inlet of pressure gradient capsules.

--best regards

Very good. Glad you could get that done in a reliable way.

--best regards

JonG, "correcting" the blue dot (now known as "+5 dB") setting involves nothing more than disconnecting one solder bridge on the circuit board and connecting another, adjacent one instead. The CMC 3--, 4-- and 5-- amplifiers all came with schematics showing where in the circuit these bridges were.

--best regards

Maurice, no, it's not. The CM 060 a/k/a CM 60 T was a transistorized version of the CM 60 microphone series which had used an EF 94 vacuum tube. The transistorized version was designed to be compatible with the power supplies for the older, tube-equipped microphones. So it has supply requirements, and a pin arrangement, different from any other solid-state microphone that I know of.

Of course, since it doesn't have a tube, the connections are simpler (e.g. it doesn't need a filament voltage). But its modulation leads are completely isolated from the +60 Volt supply that it does need--and that rules out the use of phantom power.

Attached is the part of Schoeps' 1974 flyer that shows how this type of microphone can be connected to a power supply, especially the partial diagrams on the left and right.

Please note that nearly all the microphones of this series were close-speech cardioids, with significantly reduced response below about 200 Hz and elevated response between 5K and 10K for clarity when used with a windscreen, as they often were. At the time, Schoeps engraved the cardioid symbol without any special indication of modified response for speech pickup. Since these microphones were most often sold to a company in Germany that assembled public address systems, that didn't create a problem until the microphones were then resold on the used equipment market. Unfortunately a lot of people have bought them (or their CM 640 tube predecessors) as "vintage" products of a highly-regarded manufacturer, but they don't have a "vintage" tone (not even the tube models) and were never intended or designed for studio recording. Also, the company no longer supports or repairs these microphones, nor do they have any capsules (such as a standard cardioid) remaining for sale.

--best regards

Atilla, I'm not sure which of two related models you mean--the BLM 3 or the BLM 03 C. The answer will depend on which one you have.

The BLM 3 (discontinued a few years ago) was Schoeps' original, large, square-based, rather heavy boundary layer capsule meant for floor placement or wall mounting. In terms of its electrical connections it was the same as any other Colette capsule. You could connect it directly to any Schoeps amplifier; you could also use it with a Colette active cable and/or a CUT 1 or CUT 2 filter. So if that is what you mean, then the answer is yes, because the input of a CMR is basically like the front end of a Colette active cable.

But I rather suspect that you have the BLM 03 C instead--a small, portable unit with a circular base and a permanently attached, active cable that is still a current model (see color photo below). It connects only to Schoeps amplifiers that accept active accessories, i.e. the CMC series or the M 222. The front face of the CMR has a metal ring which physically won't let you connect any active accessories to its input, since it isn't designed to power them--so it wouldn't be compatible with a BLM 03 C.

--best regards

Hello, JBond. I just read this entire thread start to finish. I can empathize with your reaction when someone re-re-re-posts already-debunked historical claims that they've found somewhere on the Internet--thus adding to the seeming consensus for what sometimes are completely spurious tales. I'm doing a long-term project of historical research for a microphone manufacturer that's just a few years older than Kudelski SA, and the frustration that I experience can be similar--including that the company itself has sometimes given out incorrect information about its own past products.

But that shouldn't be a great surprise. At a busy company, no one has time to do the kind of research that would be needed. As long as people are still around who know how things really happened, no one generally asks them, writes it down, checks the information out, comes back with follow-up questions and so on. It's usually only afterward that anyone tries to reconstruct what, by then, is no longer part of the available "institutional memory". And that reconstruction of history takes much more time than people realize--while still leaving many questions unresolved and perhaps, unresolvable.

--I've lately been using my Nagra IV-SD for playback of concerts and Conservatory classes that I recorded on it in the 1970s. That's the non-sync, wide-track (narrow guard band) version of the IV-S. The deck's electronics were modified by the late Franklin Haber, an independent sound engineer in NYC. During the pandemic I've been transferring as many as possible of my old analog recordings to digital--but that's proving to be rather difficult where the open-reel recordings are concerned, since back in the 1970s and early 80s I used Ampex 406/407. It has to be "baked" first in order to play it back without its destroying itself; I'm just learning how to do that properly.

I also own a Nagra SNG recorder, a model that you haven't mentioned here to my knowledge. Each of the SN recorders had two speeds, and for the non-stereo versions there were two head configurations as well. The SNN (the 3-3/4 ips version with 1-7/8 ips as an alternate speed, as used by film sound people) recorded full-track on the 1/8" tape, while the slower-speed versions (SNS and SNG) had half-track heads--still mono, of course. But the ultra-miniaturized electronics didn't allow for separate bias and record EQ settings for the two speeds that each model offered. So each recorder could be optimized only for one speed or the other, via record amplifier cards that differed for each of the three possible speeds. The SNN was thus optimized for its faster speed (3-3/4 ips) and the SNS for its slower speed (15/16 ips). The less-well-known SNG was in-between, in that its record amplifier was optimized for 1-7/8 ips (its faster speed), but it recorded only on half the tape width and at half the speeds of its film production counterpart.

I bought it somewhat on impulse from Hayden Labs in England when I was there ca. 1975-76 for an AES convention held in Hammersmith. I assumed that the SNG would perform at least as well as a good cassette recorder, since it was made by Nagra and the tape speed was the same. In fact, though, its sound quality was a great disappointment--especially the very severe flutter. After what I'd paid for it, it took me a while to admit that it was really no good for anything with music in it at all. But maybe Jamie Howarth's "Plangent" process can fix up those recordings some day.

--best regards

Gazwas, the rotational symmetry of Schoeps' CMIT microphones is a feature that truly differentiates them from some competing brands. For other microphone or capsule types, however, such as omnis, cardioids and supercardioids that aren't "side-facing", rotational symmetry is the usual situation that users assume implicitly.

Have you ever seen someone set up a pencil-type cardioid, aim it at the sound source, then rotate the mike until the logo (or whatever) was face up? That's not common practice, because it's widely understood that it makes no difference. When it does make a difference, it's the manufacturer's responsibility to say so, and to provide some way of showing how the microphone should be oriented.

To my mind, if something isn't a distinguishing feature, it would be misleading to emphasize it in the sales literature--as if implying that other people's microphones aren't exactly the same way.

--best regards

Off-axis rejection in any shotgun mike is highly variable as a function of both frequency and the specific angle of sound incidence. That's the nature of the interference-tube technique, which is based on phase cancellation created by path-length differences. At one off-axis angle you might find 10 dB variation in response across a given octave or two of the frequency range (a degree of variability that wouldn't be tolerated in any other type of microphone). If you move the source or the mike just 10 degrees relative to the main axis, that entire response curve will change; its hills and valleys will occur at different frequencies from before, and the distance from the highest peak to the deepest valley will also change.

As a result, no one overall decibel amount can possibly characterize a microphone's behavior in practical situations. If you graph the microphone's directivity factor vs. frequency, then you start to say something--but the sound quality in practice will still be affected significantly by factors that the graph doesn't reveal.

The length of the interference tube determines three interrelated effects. One is that a shorter tube generally causes less violent ups and downs in the frequency response for any given angle of off-axis sound incidence. A longer tube causes a greater degree of variation or deviation from flat response, depending on the angle.

Second is that, at any angle at which a given frequency is being (relatively) suppressed, a longer tube would generally suppress it more--though that's not an airtight statement, since the frequencies of maximum suppression at any given angle are also a function of the tube length, so it's true only in the aggregate.

Third--and this is something that I'm surprised that people seem to forget so often, even in this forum sometimes--is that the length of the tube determines the frequency at which the tube begins to have any effect on off-axis sound pickup at all. For any given length of interference tube, there's a frequency below which the tube is transparent to sound and has no effect on the pattern. It's inversely proportional to wavelength. A longer interference tube will begin to narrow the microphone's pattern at a lower transition frequency than a shorter interference tube will do.

(As an aside: The little microphones that have come onto the professional market recently, with slotted tubes only two or three inches long, can't possibly have any narrowing effect except on the highest sound frequencies. From their polar diagrams it's clear that the narrowing occurs above the range that matters most, and that the degree of suppression is also quite limited, as one would expect from their principle of operation. Yet people's wishful thinking seems to take over, like "Wow! A miniature shotgun microphone! Why didn't someone think of this sooner?" The answer is that the interference tube principle can't be miniaturized and isn't being miniaturized, since it depends entirely on sound wavelengths--and the slotted tubes on these little microphones are more for show than for real, no matter whose brand is on the microphone.)

--best regards

There's no extra charge for a warranty (?!!); for microphones it's two years, and capsules and amplifiers can be registered on Schoeps' Web site so that it becomes ten years. Certain conditions apply, e.g. the extended warranty applies only to the original owner, and must be registered within a year of the purchase.

I think that the charges mentioned earlier must have been for non-warranty service. In that situation, yes--if you send Schoeps a complete microphone for service, its capsule and amplifier are considered separate items. This is spelled out on their Web site, and the flat rates are given there as well, which depend on the age of the product(s) involved. https://schoeps.de/en/service.html .

--best regards

Whenever I've bought used Schoeps equipment I've sent it back to the factory for checkout. Even capsules that were claimed to be in "excellent" or "like new" condition have needed some degree of repair about half the time. I don't blame the sellers; they can be 100% honest but unaware of internal problems that may exist.

As far as changes over the years are concerned, newer capsules of some types (e.g. the MK 2 omni) are more sensitive than the ones from the first decade or two of the Colette series, thus lowering the equivalent noise of the microphone as a whole. A few types of capsule have also undergone improvements in frequency response at one or both ends of the range. For example an MK 8 with the newer, more open housing type will have more extended low-frequency response than the original type did; an older capsule can be remounted in a new housing to get this improvement.

With older capsules that need more serious repair, Schoeps may update them to some extent when repairing them. That depends on the repairs that are needed, though. if a particular capsule has sonic characteristics that you want to maintain as closely as possible, you should let them know that when you send it in, in case they have to replace major parts; they can sometimes accommodate such requests. They keep records of every capsule they've made since 1950, and update those records when repairs are made, although as of last year they no longer repair microphones older than the Colette and CCM series.

--best regards

Very glad to hear it.

The RSM 190 and RSM 191 are exactly the same microphone. Neumann didn't sell these microphones separately, but only in sets with accessories and a carrying case, and it's the accessories (mainly the required matrix box) that differ by "generation".

There have been three different types of matrix box (MTX 190, MTX 191 and MTX 191 A), with differences in cabling and powering arrangements between the MTX 190 on the one hand, and the two MTX 191 models on the other. But any of these matrix boxes can be used equally well with a microphone labeled either as "RSM 190" or as "RSM 191", as long as you use the right type of cable between the microphone and the matrix box.

The main functional difference among the matrix boxes is that the MTX 190 requires external 48 Volt phantom powering, while the MTX 191 [A] offers a compartment for a 9V battery for when phantom powering isn't available, plus a toggle switch for battery vs. phantom operation. Specifications are identical for both types of powering. Battery life is claimed to be 8 hours for an alkaline, which I haven't tested. The MTX 191 has a low battery LED, while the MTX 191 A has a "battery test" position on its battery-vs.-phantom toggle switch.

The MTX 191 and 191 A also have a 10 dB pad switch, a switch to shift the (always on) low-cut filter up from 40 to 80 or 200 Hz, and a switch that reverses the L vs. R outputs in either X/Y or M/S mode--none of which the MTX 190 has.

Speaking of low-cut filters, there is also a gradual rolloff filter for frequencies below about 150 Hz for the "S" channel (figure-8) only, in the body of the microphone itself. This filter can be bypassed by unsoldering a bridge on the circuit board. Bypassing the filter makes the stereo pickup more spacious-sounding, but of course it also increases the risk of wind and handling noise. The filter is engaged when the mike comes from the factory, but if you buy a used RSM 190 or 191, this solder bridge should be checked (pages 9 and 10 of the instruction manual) to make sure that it's set the way you need it.

--best regards

As John B. said, the DC converter circuitry in modern microphones is part of this. First-generation phantom powered microphones generally took the incoming 48 Volts and routed that through a high-value resistor to polarize the capsule. Those mikes generally had a single FET as their only active device, with an output transformer--miniaturized so as to fit into a 20 or 21 mm-diameter housing--that brought the output impedance down into the standard 150 or 200 Ohm range.

Transformers that small, however, saturate rather easily, especially at low frequencies. They restrict the maximum output voltage and thus the maximum SPL of the microphone. More modern condenser microphones generally add an active output stage which is direct coupled, i.e. transformerless. That arrangement requires substantially more operating current, but also offers much better headroom, and greatly improves the ability to drive long cable runs.

The DC converter that John mentioned improves the sensitivity of the microphone, since all other things being equal, the sensitivity is proportional to the capsule's polarization voltage, and those converters typically put out around 60 Volts. They're also almost a necessity in a modern 48-Volt microphone, since the increased current draw of the output stage causes a larger voltage drop across the 6.8 kOhm resistor pair in the phantom supply. Thus a microphone that draws 4 mA, for example (2 mA per resistor -> 13.6 V drop across 6.8 kOhms), actually receives a voltage in the low-to-middle 30s rather than 48. It would cause a major step backwards in sensitivity if such a low voltage were used to polarize the capsule.

So: The original, analog version of the Neumann KMR 81 is one of the last remaining holdovers from their fet 80 series, which began with the KM 84 microphone in 1966. It features the older, simpler, lower-current, transformer-output type of circuit, with lower headroom (as a wild guess, maybe 6 to 10 dB lower) than it could have with more modern circuitry. It still does well for its age, though--it can put out about 900 mV (when lightly loaded) if it has to, for a maximum SPL of 128 dB (again, when lightly loaded).

It's a nice-sounding microphone in my opinion. I don't know how well it does in high humidity, though; it's a traditional DC-polarized condenser, and for situations with any risk of moisture condensation, RF condenser microphones are generally considered more reliable.

--best regards

The KM 180 series uses a DC converter to boost the 48-Volt phantom supply voltage up to 60 Volts to polarize the capsule. The converter basically is a radio frequency oscillator that drives a tiny step-up transformer; its output is then rectified and smoothed.

With proper powering and a properly functioning microphone, the frequency of that oscillator is well above the audio range. However, if the microphone is defective or the phantom powering isn't up to specification, the oscillator frequency can dip down into the audible range. You can hear this if you connect the mike to an outboard phantom supply, run it for a minute, then turn the powering off while you continue listening to the microphone's output. As the stored energy in the supply and the microphone ebbs away, the oscillator will drop in frequency, and you will hear it descend through the audible range until it dies out completely.

Since Sennheiser didn't find any problem with the microphone itself, I suspect that it wasn't being powered correctly when you ran it. There have been two different versions of the KM 180-series circuitry; the changeover occurred around 2002. The original KM 180-series microphones required 2.3 mA; the later version requires 3.2 mA (in return for which they are 3 dB quieter, while keeping the same sensitivity and maximum SPL).

I suggest that you try your microphone with a different preamp, mixer or recorder, or with a known good outboard 48-Volt phantom power supply. The original version of the phantom powering standard set 2 mA as the recommended limit, and a lot of older equipment (and even some that's newer) falls out of spec trying to deliver the 3 to 5 mA that microphones commonly require today, let alone the 7 to 8 mA required in some extreme cases.

--best regards

The KM 183 is a "diffuse-field equalized" omni, which means that it was designed for distant miking. When used at medium or close range, it will have a considerable on-axis elevation in its high-frequency response--6 to 8 dB. That evens out when the mike is used at a distance in a reverberant space, since when you get far away enough, the sound reaches the microphone at more or less random angles, while that high-frequency elevation only affects the front quadrant.

On the plus side, this type of microphone would have lower sensitivity to wind and handling noise than any directional microphone. But due to the pickup pattern, you would have to get almost twice (1.7 times, technically) as close to your sound source in order to pick up the same direct/reflected mixture as even a cardioid would give you.

--best regards

The factory can update older CMC 6-- amplifiers, but it's not cheap; it involves an entire circuit board replacement, not merely installation of that shield plate in the connector well. In effect it's a trade-in.

There's no sonic difference, nor any change in performance or powering or anything else. And clearly, not everyone absolutely needs the more recent version. Still, I'm glad to have it because I record mostly live classical concerts, and I can't exactly tap the conductor on the shoulder and ask for a retake.

--best regards