Sabine Phantom Mic Rider
Dec 1, 2007 12:00 PM, By John McJunkin
Mic processor helps automate audio quality.
In thinking about devices that automate various processes (and therefore theoretically “replace” the people who formerly handled those processes), I always remember the 1958 Disney treatment of the story of Paul Bunyan that I so enjoyed as a kid. In this story, a city slicker arrives with his newfangled steam saw and steam locomotive to challenge Paul and Babe the Blue Ox to a competition. Long story short: The inventor with his technology manages to defeat Paul and Babe by stacking lumber 1/4in. taller.
The Paul Bunyan story had a profound impact on me growing up; I have never been fond of the notion of technology replacing craftsmanship. On the other hand, there are situations in which maintaining a staff of educated, experienced audio engineers is impossible — for budgetary or other reasons. And for the foreseeable future, no device will have the sentience or the “ear” to make things sound as good as a human can. But there are some simple tasks that can be automated in order to solve any number of problems. Sabine offers the Phantom Mic Rider (PMR), which it touts as being “like having an engineer in every mic.” I don't think the company means to imply that notion literally, but I was curious to discover how close the product comes to supporting that statement.
There are two versions of the Phantom Mic Rider:the PMR-GP1 for podium or table-mounted gooseneck mics, and the PMR-HH1 for handheld mics. The two versions are physically similar; each are housed in a nice black metal package measuring about 2.5"×1.2"×1.6". If you look at the device end-on, it looks like a chopped-off cam lobe from a car engine. It has standard XLR mic I/O connections on either end, and its flat front face is a security cover that can be detached to reveal the unit's controls. The Phantom Mic Rideractually comes with a small jeweler's screwdriver with which to remove the device's cover — a nice touch. A single LED protrudes through the security cover to provide information about the unit's operation. The female XLR input on top of the GP1 is countersunk, with the male XLR protruding out at the bottom. The HH1 reverses that topology, with the female XLR protruding out at the top to allow you to connect your favorite handheld mic and the male XLR at the bottom countersunk into the casing.
The Phantom Mic Rider accomplishes five separate processes that would normally be handled by an engineer. Those processes are feedback extermination (Sabine's proprietary system is known as FBX Feedback Exterminator); automatic gain control; gating (or muting, as the case may be); control of plosives; and proximity effect. Indeed, as a front-of-house engineer or as a monitor engineer, I have been expected to wring out monitors to avoid feedback, and zap it if feedback arises despite my wringing. I have also been expected to ride gain to accomplish consistent levels, and to use a gate to automate the process of turning off the mic when it has no input, or to manually mute its channel on the console during downtime. Controlling plosives and proximity effect is something I've typically accomplished with a two-pronged approach: by using a rumble filter, and educating mic users on how to avoid these things.
How does the Phantom Mic Rider stack up in our Paul Bunyan-esque comparison?
The first thing that bears mentioning is the unit's infrared gate, which turns on the mic only when motion within 6ft. activates it. This is very clever, and it may be the most important process among the five. After all, mics don't feed back or otherwise cause trouble when they're turned off. In the case of the HH1, the sensor is situated on top of the unit, where it can react to the motion of an approaching person. The GP1 is a wee bit more sophisticated, allowing the infrared sensor to be located under-table, under-podium, or right on the mic itself. The sensor is small and unobtrusive enough for the latter location. This feature, in my estimation, is actually preferable to a live engineer because it automates a process that can become quite complex in cases where there are dozens of mics on stage. Even simplifying this with the use of mute groups does not prevent the engineer from occasionally forgetting to mute (or unmute) a mic, which can occasionally cause disastrous consequences. Automation eliminates this problem outright, on a per-mic basis.
Sabine's FBX Feedback Exterminator effectively helps suppress troublesome frequencies that tend to run. I ran the setup routine for this, and I quickly figured out that the unit was “listening” for troublesome frequencies and notching them. It's not perfect, but then again, neither are human engineers in this sense either. Still, in the case of an organization that doesn't have educated staff or experienced audio professionals, I would even say that FBX is more effective. A volunteer or rookie engineer is simply not likely to have the knowledge or experience to suppress feedback as effectively. Score another one for the PMR.
Automatic gain control is nothing new, but having it in a tiny little package that connects directly to your mic is pretty novel. Yes, the use of compression and expansion can nicely “ride” level automatically, but again, having a trained engineer set it up is a necessity. I was impressed with the PMR's dynamics processing here. It wasn't perfectly transparent (which is too much to ask considering the price), but it really kept levels consistent, even with a lot of transients and dynamic changes.
The PMR's scheme for contending with plosives and proximity effect is simple and effective: a high-pass filter with three cutoff frequencies, which also work in concert with the dynamics processing to keep low-frequency transients under control. I was truly impressed with this, as well — again in consideration of the fact that it's not going to deliver the same quality as a rack full of high-end boutique gear operated by an expert.
I found the connection, setup, and adjustment of these units very simple. After matching the PMR's input level to the mic's sensitivity, I went on to run the FBX routine, find an appropriate amount of high-pass filtering, and switch on the infrared gating process, all by pressing countersunk micro-buttons with the included Phantom Tool. The concise manual makes it all very clear. You should be able to have the device up and running in a minute or two, and then be able to relax a bit with your volunteer or neophyte engineer at the console.
Sabine makes it abundantly clear that these devices are not designed for critical applications such as recording or broadcast; they are more intended for schools, teleconferencing, meetings, and podium-type applications. And the fact is that they are a bit noisy, but I wouldn't be at all surprised if Sabine is working on the next low-noise revision.
Bottom line: The Sabine Phantom Mic Rider matches up pretty nicely against its human counterpart. If your application precludes the possibility for the presence of educated or experienced personnel at all times due to budget constraints or other issues, I can definitely recommend the Sabine Phantom Mic Rider as a nice way to improve the overall quality of your audio for a reasonable price.
Product: Phantom Mic Rider
Pros: Solves numerous mic-oriented problems for volunteer or inexperienced staff.
Cons: Somewhat noisy.
Applications: Schools, teleconferencing, houses of worship, meetings, public address.
Minimum phantom power: 17V @ 9mA
Frequency response: ±1.5dB (50Hz to 20kHz)
Dynamic range: 94dB typical (unweighted)
Distortion: <0.5% @ 1kHz
Propagation delay: 0.87 milliseconds
FBX filters: Two to four fixed filters
Audio connector: 3-pin XLR
Input resistance: 20k
IR sensor detection range maximum: 6ft.
John McJunkin is the principal of Avalon Podcasting in Chandler, Ariz. He has consulted in the development of studios and installations, and he provides high-quality podcast production services.
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