Beyerdynamic SHM 22.18
Nov 1, 2007 12:00 PM, By John McJunkin
High-quality, low-profile gooseneck mic.
When it comes to simple devices such as microphones, particularly those used for commercial or install purposes, it sometimes seems as though the whole book has already been written. In the journey from the incipient invention of microphones to having near-perfect, high-quality transducers, haven't we already come 98 percent of the way? Certainly, the linearity of microphones as transducers isn't perfect, but considering our current understanding of physics, aren't we doing a pretty good job? It seems that way to me.
So why do the manufacturers continue to strive? Well, in a word, it's competition. Most of our favorite equipment manufacturers have great products that really get the job done for us, and they want to attract us to buy and use their products versus those of some other manufacturer. Nevertheless, they're all pretty doggone good these days. So why should we get all excited at the announcement of some new product? Well, that really is the question, isn't it?
Now that we're getting out to the frontiers of physical possibilities, the distinctions between products that make our lives easier or raise the bar in any little way become pretty significant. Beyerdynamic's SHM 22.18 gooseneck microphone kit raises the bar in just that way. It's a great microphone, as are many of its contemporaries, but it also has a couple of unique little features that improve the quality of the end product for its users. I spent time with one of these kits recently, and I was pleased.
The microphone itself is quite small, and that is one of its more appealing features. Long gooseneck microphones are fine for podium use, but around the corporate meeting table, a less obtrusive option is desirable. The SHM 22.18 microphone fits that bill perfectly. Its low-profile 85mm length (just a touch more than 3 1/3in.) keeps it well below the line of sight of everyone sitting at the table. By virtue of its flexible neck, it can be placed a bit farther from the speaker and tilted over a bit, rendering it even lower in profile. Moreover, because this mic is more likely to be used indoors, its foam windscreen is not terribly likely to be used, and the elimination of the windscreen (approximately 3/4in. in diameter) further reduces the visual impact of the mic in its location in front of each speaker at the table. As a matter of fact, the head of the microphone itself is 11mm in diameter (just a shade less than 4/10in.), so it really disappears, particularly considering how close it is to the table to start with.
The mic connects into the CVE 22.18, which serves as both a mount for the microphone and its power supply, feeding phantom power from its full-sized male XLR connector to its 4-pin mini-XLR male connector. Conversely, the mini-XLR feeds signal to the full-sized XLR and on down the signal chain. This mount is just a bit longer than 3in. in length, about 5/8in. in diameter, and threaded along most of its length. At the top (the end that will appear on the table surface) is a metal flange that curves gently into the tabletop. It is very pleasing, aesthetically speaking. When the microphone is not in use, a cap is available to cover the mini-XLR connector.
The low profile of the visible part of the CVE 22.18, along with the ability to cover the connector with a cap, is very appealing. In the case of a meeting in which some seats will not be occupied, microphones can be placed exclusively at the seats that will be occupied, further reducing the visual interference posed by the microphones.
The CVE 22.18 also physically protects the microphone from vibration. Alternatively, the SHM 22.18 can be connected to a beltpack transmitter from the Opus wireless system series for wireless operation.
In regard to technical specifications, the SHM 22.18 is a back-electret condenser microphone that requires phantom power. Unlike some similar mics, the Beyerdynamic is very forgiving in terms of supply voltage, with an operational range of 8V to 52V. It achieves its directionality via pressure gradient — specifically, a phase-shift network created by ports in the mic's head. Its published frequency response is 65Hz to 20kHz, and based upon unscientific listening, I believe it.
It is a cardioid mic with nominal impedance of 200Ω, and load impedance of 1000Ω. Its signal-to-noise ratio (referencing 1Pa) is 60dB, so it is a reasonably quiet microphone. It consumes roughly 3.4mA. The flatness of this mic is remarkable, with the exception of a significant bump of nearly 4dB between 12kHz and 13kHz. Otherwise, there is a gentle tilt starting at approximately 1.5kHz and sloping up to +3dB at 9kHz. The boost through these frequencies nicely enhances the intelligibility of this microphone, which is very important considering its recommended applications. Moreover, the rolloff in the low end, which commences at about 100Hz and tapers off to approximately -8dB at 60Hz, is perfect for a speech microphone — particularly one that will be used in environs with air conditioning. As stated before, a foam windscreen can help attenuate air conditioning rumble further, if necessary.
The mic's cardioid pattern achieves excellent rear rejection, which is important in this case, due to the proximity of the mic's element to the tabletop. In my test implementation, I could hear no reflections from the table surface — just the direct speech emanating from above the microphone. Regarding the quality of the speech I captured with the microphone, color me impressed. That high-frequency tilt that culminates in the 4dB bump at 12kHz to 13kHz suits the capture of highly intelligible speech very nicely. There is a little bit of noise to contend with, but not enough to cause major concern — even with several of these mics online simultaneously. The rejection of the cardioid pattern does indeed present a clear image without reflections from the tabletop.
One issue of which the user will want to be aware: These mics are a bit susceptible to plosives if they are placed much closer than 10in. to 12in. from the mouth of the speaker. A bit more distance is in order, and that extra distance does not negatively affect the quality of the signal in a palpable way whatsoever. Beyerdynamic touts “high gain before feedback,” and the cardioid pattern of the mic does indeed grant this capacity, which is important if live monitoring will happen in a teleconferencing application.
As Beyerdynamic's marketing touts, the SHM 22.18 microphone blends “into each architectural ambience perfectly.” I couldn't agree more. Not only does it manage to stay out of the way from a visual standpoint; it captures the voice of the speaker in a high-quality way. The mic's frequency range works perfectly for speech. The design is well planned, and the execution is excellent, as well — the mic has a look and feel of quality, which comes as no surprise from Beyerdynamic.
In the future, if any of my podcasting clients require an unobtrusive, high-quality mic for the conference table, I will not hesitate to specify this microphone.
Product: SHM 22.18
Pros: Good quality, visually unobtrusive microphone.
Cons: Plosives are a small issue if mic is too close to speaker.
Applications: Table or desk installation for meetings or conferences.
Transducer type: Condenser (back electret)
Operating principle: Pressure gradient
Frequency response: 65Hz-20kHz
Polar pattern: Cardioid
Open circuit voltage at 1kHz: Approx. 15mV/Pa
Nominal impedance: 200Ω
Load impedance: 1000Ω
S/N ratio relative to 1 Pa: 60dB
A-weighted equivalent SPL: Approx. 26dB
Supply voltage: 8V-52V phantom power
Power consumption: Approx. 3.4mA
Connection: 4-pin female mini-XLR
Length: 85mm (3 1/3in.)
Head diameter: 11mm (4/10in.)
John McJunkin is the principal of Avalon Podcasting in Chandler, Ariz. He has consulted in the development of studios and installations and provides high-quality podcast production services.
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