Wireless mics are ubiquitous in houses of worship, from those with just a few pews to huge venues with seating for the multitudes. Given the widespread adoption of this useful technology, what challenges are churches facing as they expand their systems, enhance their productions, and plan for the future?
How do those plans fit within ever more saturated frequencies, as communications of all sorts fill the open spaces and compete for available spectrum?
CPM spoke at length with several dealers and installers who have contributed their thoughts and experiences, and discussed the challenges and opportunities their customers are facing with wireless.
Wired vs. Wireless
Surprisingly, given that wireless units are more costly per channel, more and more applications that traditionally were filled by wired microphones are going wireless. Mike O'Rourke of Peach State Audio in Suwanee, Ga., states that for his company, they sell “easily three to one, wireless to wired.” About the only wired microphones are on a podium or in fixed choir positions. Drums will often still have wired mics, with the other instruments using DIs or going wireless.
Almost all vocalists are wireless, providing more range of motion as well as offering the mix engineer more flexibility for channel assignments and positions, since hard wire does not have to be run to a particular location. Donnie Haulk, CEO of AE Global Media in Charlotte, N.C., notes that wireless “cleans up the stage” and is easier for the lay person to use since the receivers are “permanently wired into the system” and the wireless transmitters are able to be flexibly assigned for different applications and locations.
Haulk sometimes uses wireless even for choir mic'ing, especially when the choir is on portable risers or varies its location. He will use choir mics on boom stands to position them overhead, connected to bodypack transmitters to relay the signal to the board.
700 MHz Fallout
The FCC ban on the use of wireless microphones and similar devices within the 700 MHz UHF band, which went into effect mid-2010, created significant difficulties for many houses of worship that owned systems within this band—ones that were still operating well but were now declared illegal.
John Fuqua of All Pro Sound in Pensacola, Fla., observed that just two years ago churches had to spend inordinate sums to upgrade due to the FCC decision. Most churches, he notes, are still “nursing their wounds” because of this expense, and are wary to invest in the latest wireless innovations when the previous mandated upgrade was so recent.
According to Jon Sheets of Sound Productions based in Irving, Texas, ongoing FCC changes are at the core of most wireless challenges, as the agency tries to accommodate all of the competing wireless usage demands within a finite spectrum. Changing regulations compress the frequency bands that are available for wireless microphone use and raise the uncertainty that a selected wireless mic's frequencies will function longer term without interference in a given location.
The FCC-mandated transition to digital television (DTV) in the mid-2000s dealt quite a significant blow to single-frequency, fixed wireless systems, rendering a greater portion of the UHF spectrum unusable. Mike Paul, technical director of North Hollywood, Calif.-based Location Sound, notes an additional effect that clearing the 700 MHz band had on existing television broadcasters within that spectrum, by forcing them to move to formerly unassigned lower TV channels in the various market areas—making already dense spectrum more crowded.
The DTV transition also ended the practice of slotting wireless microphone frequencies within the clear spaces between the video and audio carrier frequencies within the particular TV channel. Creating even more uncertainty, the pending “white space” rulings will allow multiple devices (and not just low-power, short-range ones) into the spectrum between television channels and will make finding consistently clear channels for wireless mics more difficult. Here is where some of the latest technologies will provide relief.
Enter the Latest Technologies
Wireless systems that can be tuned across a several MHz band are widely available, even at modest price points. They typically encompass the spectrum of three or more adjacent television channels, and hopefully one or more are not occupied by an existing DTV broadcaster in an area. When purchasing new wireless systems, choosing the best frequency band for a given region is a key decision.
In combination with tunable wireless systems, according to O'Rourke, the greatest help for both customers and dealers is that manufacturers have created “clear scan” technology in their wireless units; this innovation has really helped the wireless industry, and scanning is “creeping down into the lower price points,” he reports.
The technology uses the receiver to detect existing wireless signals across its entire operating band, and then suggests open frequencies that can be used without interference. Most of these systems have pre-coordinated groups of wireless channels that will work together without interference, and all a user has to do after the scan is set the receivers and their associated transmitters to the suggested channels to have a coordinated multi-channel system. Some units even provide a method to tune the transmitter wirelessly to the receiver via an infra-red (IR), digital, or similar link.
Antenna distribution is integrated into some wireless receivers, where several units can use the same set of antennas to receive the signal. This method not only relieves the “antenna farm” (an unsightly mass of antennas), but can also lead to better antenna positioning and more consistent results. Most manufacturers also have separate units, sometimes known as multicouplers, that provide the connections for multiple wireless receivers and ease the use of remote antennas. Sheets finds that antenna distribution is especially important for larger wireless installations.
Fuqua's experience is that the quality and reliability of wireless systems are relatively equal across the major brands. Purchasers make their choices based upon desired features, microphone types, and price points.
Digital Wireless
Some wireless manufacturers are now incorporating digital encoding of the audio onto the transmitter's radio frequency that, when applied with other technologies, can allow more channels to be run without interference within a given band of spectrum. Some of these systems operate in the unlicensed 900-MHz and 2.4-GHz bands, and others in the licensed UHF television band. Fuqua notes that although this technology is relatively new, it is “the shape of things to come as bandwidth gets tighter and tighter.”
Digital wireless microphones are currently offered at various price and feature levels by Shure, Line 6, Sennheiser, AKG, Sony, and others. O'Rourke says he has already sold a great deal of digital systems in the mid price points, and concurs that this technology with be part of the solution for crowded spectrum. Haulk, however, finds that he still is using more of the analog UHF systems at the mid to higher price points, in part because of the maturity of that technology and he “likes the sound of them better.” Offering a different opinion, Sheets and O'Rourke say that the sound quality of many of the digital systems is quite good and their companies recommend them.
Because some of these systems operate in different parts of the RF spectrum than the traditional UHF band, they can open up opportunities for more wireless channels in an existing installation.
Frequency Coordination and Other Considerations
Building a new wireless installation or adding channels to an existing one requires technical knowledge and care, and the dealers interviewed provide a variety of services to make the process successful. One of the most basic services is to help the purchaser select the correct frequency bands for their location and applications—so that the wireless can function without interference from television channels and other wireless devices. Paul finds that church audio techs have become more “technically savvy,” although he reports that they still need assistance with choosing the best frequency bands and coordinating frequencies, as well as with peripherals such as antenna distribution systems and their proper placement.
Haulk adds that for installations of more than six to eight channels, more detailed frequency coordination is essential. With very large systems that incorporate 20 or more channels of wireless microphones (and/or in-ear monitors, wireless intercom, etc.), a careful scan is recommended, followed by selection of higher performance, “frequency agile” wireless systems and exacting frequency coordination. Sometimes a scan over two or three days, focusing on the times when the system will be used for worship or other activities, is recommended—a process that requires a skilled technician with the proper equipment, the experts report.
Decisions for Larger Systems
Some houses of worship will require only a handful of wireless channels, or are situated in rural areas where few competing wireless frequencies or strong digital television signals are likely. In such cases, moderately priced systems with less sophisticated features can provide a satisfactory, interference-free result. However, in urban areas with densely packed communications of all types, and where flawless performance and excellent audio results are required, choosing a wireless system that a church can grow with necessitates a series of important decisions.
O'Rourke describes a process he uses at Peach State Audio with a church that is buying wireless. In the initial discussion, he has the person consider “where they are going” with the wireless system—to think through the possibilities to the end rather than just filling the immediate need for a pastor's wireless or a mic for a vocalist. By visualizing the foreseeable possibilities, the current two channels might eventually lead to 12; an investment in a higher quality wireless system to begin with will make compatibility and interference avoidance easier in the future, as well.
For larger systems especially, the configuration of the receivers and the space they fill must be considered. Half- or third-rack sized units with fixed antennas can be fine when two or three are on a table or the edge of a balcony, but when a house of worship has multiple channels, such a setup can exacerbate RF problems. More professional receivers with BNC antenna connections and pass-through connectors, even in half-rack formats, can be rack mounted—giving two channels in single rack space and the possibility for efficient antenna distribution. And several of the higher performance systems pack more than one channel in a single-rack chassis; Fuqua, for instance, cites the Shure ULX-D, which provides “a four-channel frame complete with antenna distro.”
When the audio is being broadcast to radio or television, an even higher level of consideration is required. Interference effects and dropouts are not tolerable, multiple wireless mics along with wireless in-ears and intercom are probable, and the location is more likely urban with the potential of heavy DTV interference. With its focus on film and television production, Paul of Location Sound suggests using the most technically sophisticated systems with tighter tolerances, so that more channels can be used together in the same amount of spectrum and with software solutions to monitor the whole system integrated into the wireless units.
Price Points
Though usable wireless systems can be had for a several hundred dollars, such systems are best used when only a few channels at most will ever be needed. For “half a dozen wireless” installations, O'Rourke has had success with units at around a $300 to $350 price point; the majority of his customers, however, invest about $500 per channel. Fuqua finds that his customers typically spend $400 to $500 per channel for a basic wireless system, and $1,000 to $2,000 for broadcast-level churches. Haulk says that his average customer spends $600 to $800 per channel for a quality system, and $1,500+ for a “production church.”
It is likely that you are or soon will be considering a wireless purchase, either for a new system or adding to an existing one. Consider what your audio needs will be several years from now as you make your decisions, learn about the various technical solutions to wireless problems, and use your dealer's expertise for recommendations on frequency choices and coordination. Remember that the quality of the entire audio chain begins with the input—in this case, the wireless microphone.
