Microtech Gefell M 930 Microphone

by Dr. Fred Bashour

Product Points

Applications: Studio Key Features: Cardioid pattern; one-inch diaphragm; choice of finishes Price: $2,350 Contact: Microtech Gefell/C-Tec at 604-942-1001, Web Site. Plus + Extremely versatile microphone set + Purpose-built X-Y and M/S mounting bars available Minus - Cardioid-only (M 930) or hypercardioid-only (M 940) models. The Score In my opinion, a pair of Gefell M 930 mics is the lowest-priced "fancy, expensive, German" mic set suitable for world-class recording situations. And it's the quietest mic I've ever used.

Sure, I've read all those Microtech Gefell ads over the past few years - about the fact that they're the "other branch" of the Neumann family tree - but I've never had the opportunity to try one until now. And, wow, was I impressed! As my readers know, I own tweaked-out pairs of just about every vintage Neumann tube mic ever made, as well as a bunch of more modern - yet still expensive - mics. I'll state here, at the outset, that this modestly-priced but beautifully machined set of microphones easily holds its own with the other members of my collection and, in one important aspect, beats them all, hands down.

Features

Think "Honey, they shrunk my M 49!" Well, that's just about what the Gefell M 930 looks like - about one third the size of my vintage 49s, but otherwise very similar. The spec sheet gives its dimensions as 118 mm x 46 mm, but to me, it is three inches long and about an inch and a half across. Tiny! Despite its diminutive size, it contains a full-size 1-inch (single membrane) diaphragm, and amazingly hip electronics. It can be supplied in two different finishes: satin nickel and dark bronze and, as mentioned previously, one can purchase either the cardioid M 930s ($2,350), or the supercardioid M 940s.

The Gefell electronic impedance converter (amplifier, to the rest of us) uses a new circuit topology said to reduce the noise floor to an extremely low level while also raising the mic's maximum output capability - giving the M 930 a clean, distortion-free sound over an extremely wide dynamic range. In practice, they seem to need about 7 dB less preamplification than any of my vintage tube mics. Naturally, they are phantom powered.

In Use

Over the test period, I tried the review pair out on vocals, piano, harpsichord, strings, drums, clarinet, and percussion, and was always impressed. What's more, in most scenarios, I compared them directly with my standard reference mic - a 0.9-micron Stephen Paul Audio-modified Neumann SM 69 stereo unit. The latter mic, which costs more than $10,000, of course sounded a little airier, and could be used considerably farther away from the sound source before it lost resolution, but the stereo pair of tiny Gefell mics was definitely in the same ball park, "sound category"-wise.

Both had that "big, bold Neumann" sound, the M 930 actually seemed to have a deeper low end, and was definitely quieter. In fact, it turned out to be the quietest mic I own! The main difference between them lay, in fact, in their resolution attributes. My SM 69 reproduced the very quiet "tick tocks" of the antique mantel clock in my living room with amazing fidelity, while the M 930s mushed them all together into the general ambience.

The M 930's high end is very smooth, though obviously not as extended as that produced by a super-thin 0.9 micron Stephen Paul Audio diaphragm. While most lower-priced mics always sound "tizzy" to me, the Gefell M 930 did not. Rather, it sounded just a tidge dark, but very smooth. I attribute a lot of this smoothness to its single-diaphragm design. The mic took both shelving and peaking EQ very well, never sounding peaky or sibilant. And on bright instruments like harpsichord or twelve-string guitar, it sounded awesome - just right!

Over the past few years, I've become increasingly impressed by modern solid state technology, and the electronics shoehorned into the M 930 were no exception. I couldn't figure out how to get it open (I'm told that the capsule and electronics are manufactured as a single unit), but I can certainly state empirically that the mic sounds both warm and clear, very unlike my long-standing impression of older solid state mics.

Stereo microphone

techniques

Since the pair of M 930s submitted for review was matched and supplied together in a nice wooden box - along with both ORTF and M/S stereo bars, and since I use primarily stereo mics for my classical recording projects, I did a lot of my testing in that mode. Gefell's SH 93 stereo bar enables the two M 930s to mount "nose to nose," and be easily angled between 45 degrees and 180 degrees apart via markings engraved into the SH 93's clamps. Setting a pair of them up is quite quick and easy and, in truth, the main difference between this arrangement and the use of a "regular" stereo mic is simply that one needs to rig two standard cables, rather than one special stereo mic cable.

For an ORTF arrangement - in which two cardioid or hypercardioid mics are separated by 170 mm and angled out about 110 degrees - one uses Gefell's TD 93 tandem bar with a pair of M 930s. Combined with a pair of either M 930s or M 940s, Gefell's two nicely-machined mounting bars offer a cost-effective equivalent to a dedicated stereo microphone. The ORTF method (which combines both time and intensity differences) gives a more spacious stereo result, but without the perfect phase coherence of the true coincident X-Y arrangement. My own trick is often to use multiple stereo mics - employing both setups - and make my imaging decisions in post-production. A pair of M 930s is thus more versatile than any single stereo mic, and their tiny form factor makes various stereo arrangements quite easy to accomplish.

Conclusion

I liked the M 930s so much that I bought them. While they are not my most high-end mics I am sure I will use them a lot more than some of my more expensive models. I would not hesitate to use them alone to record classical concerts, or even to spot mic groups of singers in live performances. And the next time I have to record a lute or clavichord (two of the quietest instruments in the world), I sure know which mics I'll be using!

Dr. Fred Bashour is a regular contributor to Pro Audio Review. He holds a Yale Ph.D. in Music Theory, and works as a classical music producer/engineer - with credits on hundreds of recordings.