Gear & Now: Wireless Mics
Posted Mar 28, 2007

No, really—the sky is falling! You may have heard that before, but this time, it really will come true. The sky—at least, the space above your head that's used for radio frequency transmissions—is falling, and could cease to exist. Anyone using a wireless audio mic should take notice—certainly, some of the manufacturers are!

By way of brief background, you know changes to the analog television spectrum are coming, as is the drop dead DTV date (April 2009). Well, the Federal Communications Commission (FCC) will probably also sell off the 700MHz frequency at that time, when it becomes "available."

We could face significant problems in using wireless microphones for live video coverage as a result, especially as the Commission has already voted to allow "fixed wireless devices" to operate in the broadcast band.

The FCC is taking input from industry participants about the nature of that spectrum (being called "white space") and the effect such devices might have when operating there, whether they should be licensed or unlicensed, whether mobile devices should be allowed, and so on. This spring, the FCC is slated to begin testing different wireless devices, and it's supposed to table a report by the end of the year.

Depending on those results, devices could hit the market early in 2009—just in time for the sky to fall.

Although the FCC is going to test for possible interference with digital televisions, it apparently is not going to test interference to wireless audio microphones. Broadcasters, production companies, event videographers, equipment manufacturers, and industry associations are—or should be—directly involved.

For example, Shure, Total RF, and the Association for Maximum Service Television Inc. (MSTV) are among those involved in recent meetings in Washington, D.C. with U.S. congressmen and the FCC.

Commissioners and staff there were told how important wireless mic systems were to the production community in general, and they should be protected from potential interference.

MSTV published a report on the prospect of harmful interference from unlicensed wireless devices to broadcast transmissions, and by extension, ENG crews in the field relying on VHF and UHF frequencies for authorized wireless mic transmission.

It's not just the United States, of course; Canada, the United Kingdom, and European countries are all facing some sort of spectrum management issues, if not an impending sell-off of available spectrum.

Sennheiser, by the way, is on record with statements like "the consequences . . . would be disastrous," and "no . . . room for radio microphones," and "not reserving a spectrum for wireless microphones would mean the end . . ."

Sounds pretty serious, huh? Sennheiser nevertheless says it is optimistic about the potential for a satisfactory resolution.


figure 1Sennheiser's "Frequency-Agile" Wireless Systems
But if you need to know any more about the move to "frequency-agile products," just look skyward. Actually, that's the phrase Sennheiser uses to describe its products, like the newest 5000 series: 32 custom frequencies are programmed within the switching bandwidth of 36MHz; another 20 frequencies in steps of 5KHz can be programmed and stored by the user.

The company's new slot-in receiver for pro video cameras is a good match for the SK 5212 bodypack transmitter, for example, as well as the 5200. Sennheiser is now showing beta software that can control and monitor mic systems from a PC (the full release should be available by the time you read this).


figure 1dB Technologies
DB Technologies says it sees the future of wireless transmission as digital, and in the 2.4GHz range. Its new DWS2400 system includes handheld mic, 16-channel transmitter, and receiver. It gets to that range (at the upper reaches of the UHF band) with a special built-in antenna. Operating with 9 V batteries and an LCD readout of signal and power strength, the system works with condenser-capsule or dynamic hyper-cardioid mics as well.

In a more traditional vein, the new TOA 5000 Series wireless microphone systems operate in the 692-722MHz band with up to sixteen simultaneous systems. Transmitter options include handheld condenser, lapel, or headset mics. Transmitters take a single AA battery, and are rated for up to 10 hours of continuous operation. Receiver models (16- or 64-channel) feature a frequency-scanning function and transmitter battery-status indicator.


figure 1Azden
The new Azden 300LT is a complete system with body-pack transmitter, electret condenser lav mic, and receiver. The receiver and transmitter offer 240 frequencies (794-806MHz) to choose from.

It's smaller than the company's 500 UHF wireless receiver, and easy to put on those newer, smaller DV cameras (the attached shoe-mount takes the receiver horizontally). There's balanced mini-jack mic output, headphone out, and LCD display with selected frequency, reception quality, and battery life info displays.

The belt-pack transmitter works with lavaliere and headset microphones. A pair of AA batteries provide power.


figure 1Behringer
For hosted sports- or school-video production, there's a nice new headset microphone featuring a Panasonic condenser transducer mic, due this summer from Behringer.

Its Ultralink UL2000B true diversity headset system offers up a choice of 320 transmission frequencies, including user-tunable transmit frequencies and three presets for eight channels each.

The body-worn transmitter operates with a 9 V battery, and there is a local mute function and low-battery indicator on the unit. Receiver operation is managed through a comprehensive menu and LCD screen. The receiver also features a switch-mode power supply with easily interchangeable AC plugs for maximum flexibility (100-240 V). It's a fixed unit, so a 19" rackmounting kit is included.


figure 1Nady
Nady's 351 ultra-compact receiver is nice for any videographer, being easily camera-mounted with a supplied cable or bodyworn. There's room for a slide-open 9 V battery compartment, LED lights for low battery and receiver signal, and not much else.

There are two available transmitters, handheld or bodypack, with an omni lavaliere or headset mic, with mini-jack connections and input level adjust. An Off/Standby/On switch allows audio muting with the transmitter "On."


figure 1Zaxcom
Zaxcom's new ZFR800 handheld wireless recorder and TRX800 handheld wireless mics are making their debut, having been announced last year. These systems provide internal recording capabilities for applications where sound quality and mobility are paramount, and the system produces a timecode-referenced recording as backup.

It's supposed to shine in live and live-to-tape applications where good sound is critical, or where wireless transmission might be affected by interference or limitations in the available frequencies.

Think they knew the sky was falling?

Lee Rickwood is a media consultant and freelance writer.