The next three years will likely involve substantial changes in the average church's wireless working environment. Choosing a wireless microphone for your worship service is not necessarily as straightforward as searching on Google for the best deal. A number of other factors must be considered in addition to “how much does it cost?” CPM explores what to look for when adding wireless mics, giving ideas for smaller and larger churches, and those located within potentially high-interference areas.
In addition to “how much does it cost?” consider these questions:
1. How many channels of wireless will be running and in what frequency bands?
2. How critical is audio quality to the service?
3. Is the church located in an area with many active DTV broadcasters, or is it expected to have many broadband wireless services operating in those same bands?
4. Will the Broadcast Incentive Auction’s pending clearing of large swaths of the 600 MHz band affect current wireless and future choices?
5. How broad is the skill set of the audio team?
Wireless Mics & the Incentive Auction
Because it will greatly affect the available wireless spectrum over the next few years, the current FCC auction of 600 MHz spectrum is front-and-center. As you may remember from the 700 MHz clearing a few years back, wireless mics operating in the affected bands were prohibited from operating. Perhaps you had to trade them in for lower band wireless.
The same thing is now happening to most of the 600 MHz band, and once the auction completes (likely by early 2017), users of wireless mics operating in those cleared frequencies will have only 39 months before they must retire them.
The cleared spectrum is being converted mainly to mobile broadband services, and TV broadcasters will be “repacked” into lower bands. So your first action is to check your current inventory and determine whether mics operating in that spectrum will need to be replaced over the next three years.
Also note that the definition of wireless microphones includes handheld and beltpack/headset mics, wireless instrument systems, in-ear monitors, IFB systems, and wireless intercom. All of these items must be part of your plan. And for larger churches, if you are regularly using 50 or more channels of wireless, you could be eligible to become a licensed user. Licensing will give your operations priority over any unlicensed user that might create interference, and allow you to use the newly authorized mid-900 MHz and 1.4 GHz bands, when that equipment becomes available.
Selecting Quality
A wireless mic can be purchased for under $100 or may entail an investment of several thousand per channel—ranging from systems with very basic features and passable performance to professional quality audio and versatile frequency and networking options. Excellent systems for many applications can be found for several hundred dollars per channel.This middle range has greatly improved in terms of audio quality and features since the 1990s. What are some key differences?
Most current wireless microphone systems are “frequency agile,” where the user can select among several or many different frequencies. This feature can range from a handful of pre-coordinated, compatible “channels” covering a modest range of RF spectrum to full access to any frequency over bandwidths of 75, 150, or more MHz. Especially for professional applications where many microphones are in use within an urban area with multiple DTV station and other spectrum users, the ability to set your wireless to a particular clear frequency is paramount. Many mid- and high-level systems also have scanning abilities to detect existing interference and suggest usable frequencies.
The more professional (and higher priced) wireless systems will have better, more linear radio transmitters and better filtering within the receivers, lessening the impact of intermodulation between multiple transmitters and allowing more channels of wireless to operate simultaneously without interference. Many also offer monitoring and control software so that sound techs can detect and deal with potential problems quickly. The receivers can be connected and communicate together, and share antennas via internal or external multicouplers—allowing specialized antennas to be mounted remotely to counteract difficult RF problems. More upscale receivers typically feature balanced XLR and even digital outputs, will often have internal power supplies, and may have multiple receiver modules in 1RU.
Another aspect of quality is the actual microphone head mounted on a handheld transmitter, or the headset or lavalier mic offered with a bodypack. In the latter case, it is usually possible to connect a better performing mic.
Analog or Digital?
Both analog and digital wireless technologies are available in moderately priced systems, as well as in professional-level wireless. Digital wireless systems are much more immune to audible interference effects, and in my experience perform reliably and sound excellent—not requiring companding or analog squelch circuitry. The digital technologies can also help with fitting more wireless channels into a smaller amount of RF spectrum. Many of the moderately priced digital systems operate in the 2.4 GHz or 900 MHz unlicensed bands, though a few join the touring/broadcast-level systems in the UHF band.
Frequency Bands
If you are only operating a few channels of wireless, it will be relatively easy in most locations to run them all within a relatively small swatch of UHF, VHF, or Wi-Fi (2.4 GHz) spectrum. However, if you have dozens of channels to contend with, taking advantage of several different spectrum bands may be wise. For example, wireless intercom could be placed in VHF, 1.9 GHz, or 2.4 GHz rather than in UHF; excellent systems are available in all three bands. If you’re adding wireless capability to another location on-site, or for the music team, consider a 900 MHz or 2.4 GHz system for those few extra channels.
Be aware that you may be competing for bandwidth at your location, that the airwaves are quite full in some areas of the country with high-powered broadcast signals, and that the lower UHF bands are likely to become more widely used by TV when the incentive auction “repacking” is complete. Over the coming years, consumer “white space devices” may also compete for the spectrum, adding greater uncertainty and the possibility that what is a clear channel today may have interference on the next. So, look for flexibility in your wireless choices, and learn about your wireless environment—including in some cases scanning and “mapping” it for spectrum to avoid.
Smaller Church
Smaller churches using very few wireless microphones—perhaps a pastor headset, announce mic, and one for the choir soloist—may not have to be as selective in their choices. Especially in a more rural area with few on-air broadcast signals, an inexpensive fixed-frequency system might even be a viable option, as long as it provides sufficient audio quality and reflects the quality of the overall audio system. I would still recommend at least a modest frequency-agile system.
Entry-level receivers will typically feature fixed antennas, so make sure to position them so that they are within line-of-sight with the transmitters, and test for coverage and audio anomalies. Some, but not all, of these systems will feature an XLR as well as a quarter-inch connector for your mixer. To avoid interference when choosing UHF or VHF systems, make sure you know which TV channels are operating, and note the frequencies of any existing wireless equipment.
For a relatively modest investment, several of the 900 MHz and 2.4 GHz digital wireless systems operate in license-free bands above the TV broadcast range, and will accommodate several simultaneous channels. These models are easy to set up and run, often do their own frequency coordination when a new unit is added, are reliable, have options for handheld, headset, and instrument applications, and sound quite good.
Mid-sized Urban Church
For up to perhaps a dozen channels of wireless (mics, IEMs, intercom) in a more crowded RF environment, consider semi-professional 2.4 GHz or UHF systems operating in the 470-578 MHz spectrum, with scanning features and the ability to select compatible channels. Make sure that they are frequency-agile over several UHF television channels. To achieve the desired quantity of channels, you might spread them out over both bands, while maintaining consistency for specific applications—such as having the same type of wireless handheld for vocalists or headset for the pastor, assistant pastor, and guest speakers.
Choose a higher end analog or a digital system, with rack-mountable full or half-rack receivers, the ability to detach or remote antennas, and informative displays and controls. They will likely be connected to a good sanctuary sound system, so make sure the necessary connectors are provided. Expect to spend several hundred dollars per system for well-built, reliable wireless that provides higher quality audio performance.
Full-production Church
If your services involve many channels of wireless, a campus where events in several rooms are held simultaneously, or if you’re broadcasting or streaming to reach a wider congregation, ensuring problem-free operation is critical. The local airwaves are likely home to many DTV stations and other sources of interference. If you’re running over 50 channels, apply for a license.
Select professional wireless systems with the linearity to allow multiple, more closely spaced channels to operate together and resist interference, and the flexibility to monitor and easily change the frequency of individual channels if problems are detected. Especially in larger sanctuaries, antenna combiners and remote antennas may be required. Most of these receivers feature between two and eight channels per 1RU unit, and in some cases modular receivers can be added as needed. Consider placing some of your channels into 2.4 GHz, 900 MHz, and VHF.
Run scans over several days to map the RF environment and know where you can place your channels, and become familiar with the FCC’s TV Query Broadcast Database. Begin transitioning any equipment in the 600 MHz band to lower UHF bands. Use monitoring and control software to give you a real-time visual window into your wireless systems.
Making the Choice
When choosing your next wireless, many excellent systems are available at a relatively modest price. Don’t hesitate to purchase higher quality systems, since the microphone is the critical first link in your audio system. Take stock of what you’re currently using, and hopefully you won’t have many 600 MHz wireless systems to replace over the next few years. With some planning, the transition will go smoothly.
Gary Parks has served as marketing manager and wireless product manager for Clear-Com Intercom Systems. He has also worked with loudspeaker and wireless product management at Electro-Voice, performed technical writing at Meyer Sound, and worked in RF planning software sales with EDX Wireless. He is a freelance writer and can be reached at garycparks1@gmail.com.
