Specifier’s Guide to Microphones: Don’t Drop the Mic
Microphones are small, yet mightily important, components of a stellar church sound system.
“For want of a nail, the shoe was lost; for want of a shoe, the horse was lost; for want of a horse….” and so on. The logical outcome of that aphoristic progression needn’t be as dire for a modern church as it might have been for a Revolutionary-era general, but for AV consultants and design/build contractors in the midst of ground-up planning or even mid-level renovations, the focus of sound-system design tends to be placed on the major components—the consoles and the amplifiers and loudspeakers. “Microphones are often an afterthought in the big picture,” says Mark Donovan, applications engineering manager at Audio-Technica, Stow, Ohio, and a former consultant himself. “But you quickly realize once services and events start taking place just how important for each church’s specific needs having the right microphones on hand can be.”Spectrum changesThe recently concluded Federal Communications Commission (FCC) series of auctions will have radically overhauled the radio frequency (RF)-spectrum landscape once all of the reallocated frequencies have been finalized. The short version is that the 600-MHz spectrum band has been largely declared off limits to professional wireless users, including houses of worship. This follows by about four years a similar RF displacement, that one affecting the 700-MHz range. All told, wireless microphone users will have lost the better part of 200 MHz of the most desirable UHF spectrum. Systems manufacturers have been bringing out replacement products that utilize other frequencies, but consultants will be looking at a much more diverse RF landscape that they’ll have to guide their clients through over the next several years.“Consultants should definitely understand the ramifications of the spectrum change that will take place during the next two to three years,” cautions Karl Winkler, vice president of sales and service at manufacturer Lectrosonics, Rio Rancho, N.M. “Most wireless-mic users will lose access to the band between 614 and 698 MHz. This means that their clients should start budgeting for replacement units, and/or look into any re-tuning of their existing units that manufacturers may offer. This also means that the remaining UHF spectrum [470-608 MHz] will become more crowded in the future, with a greater number of TV stations in that zone, as well as all those wireless microphones. This will mean that the systems that their clients plan to use should be of generally better quality, to avoid interference and provide high performance in what is to be a tougher RF environment. “There is also new equipment in several frequency bands in addition to the UHF bands. The VHF range from 174-216 MHz offers some promise, although larger antennas are generally required to ensure the best performance. This zone will also become more crowded, as some TV stations are moving from the 600-MHz band down into these frequencies. The 2.4-GHz band has been used for wireless microphones for some time already, and there are also new products there. The issues of concern are that this band is already quite crowded, and generally it is [unrealistic] to expect more than a few channels of wireless mics to work well here. Nevertheless, if all that is needed is to add two or three channels, and the UHF band is full, this is a band to consider.”Michael Moore, who handles industry relations and market development for Shure Inc. in Niles, Ill., points out that there’s still sufficient time to make long-range decisions about wireless microphones, with a transition period of 39 months. And since the FCC is making licensing available to any entity that “regularly” (the FCC’s qualifying term) utilizes 50 or more channels of wireless systems, that encompasses large HOWs as much as it does performing arts centers, giving many churches more certainty about their wireless operations in the future. (Joe Ciaudelli with Old Lyme, Conn.’s Sennheiser, the company’s point person on spectrum issues, notes that the definition of wireless microphones now also includes in-ear monitors, intercom systems and interruptible foldback/IFB systems.) On the other hand, Moore adds, “With new digital wireless technology, we have also been able to increase channel counts into smaller spaces. In fact, since smaller churches need lower channel counts, there’ll be a greater number of spectrum areas they can use, including 2.4 GHz or higher ISM spectrum, like 902 to 928 MHz.” Moore says the first step is to determine how many channels a church needs. That, he says, will help determine which models and which part of the spectrum will work best for them. But, he cautions, it’s important to think ahead. “You may need 10 channels now, but if you need to expand in the future, will those same models accommodate additional future channel count?” he asks. HOW users will also have to decompartmentalize their thinking, looking at a church campus as a whole. “You might have someone focusing on the sanctuary but not realizing that the wireless being used in the classrooms in the next building could be potential sources of interference, depending on the frequencies they’re all working on,” he explains. “Frequency coordination will need to start at the very beginning of the process.”Impact of worship style Churches transitioning between traditional and contemporary worship - music styles, or planning to accommodate both, will want to pay attention to their microphone choices, says Donovan. “When you have a 40-voice choir, you can do fine with four or five microphones on boom stands or suspended from the ceiling, but when you have a dozen contemporary praise vocalists on a stage moving around, then you’re going to want to use something more flexible, go wireless so they can move around more easily on stage, and switch to handheld condenser mics,” he explains. “You have to take into account the dynamic nature of contemporary praise-and-worship music—vocalists move more and they may change positions within the group onstage. Wireless and handheld gives them the freedom to move about, while condenser microphones can accommodate a wider range of vocal styles and power.” Donovan, who was previously a consultant and a contractor on HOW AV projects, adds that fewer microphones makes for a cleaner look onstage, another reason to consider wireless. “When I was working with a praise band years ago they had 13 wired microphones on stage and it looked terrible,” he recalls. He suggests using the same make and model of microphones for vocals but notes that certain singers with particular vocal qualities, such as exceptionally deep baritones, might require a specialized microphone or two in the church mic closet. “But aside from that, the baseline of the same make and model makes it easier for the audio technicians to know what things will sound like and makes things less complicated,” he says. Only one wayThere is a lot of not-unwise common wisdom around unidirectional microphones, and many HOW users like them for their perceived high degree of rejection of unwanted noise. However, that’s not always the case. “Unidirectional microphones can provide some additional rejection of surrounding noise, but they are more challenging to work with than omnidirectional mics: expect more handling noise, wind noise, a higher noise floor, and more issues with microphone placement,” explains Chris Countryman, president of manufacturer Countryman Associates in Menlo Park, Calif. “Clients often think they need a directional microphone when moving the microphone closer yields better results. That said, if you need every dB of isolation, a good directional mic could do the trick.”However, Countryman adds that consultants ought to also recommend that clients acquire key microphone accessories, such as windscreens. “A little wind is a big deal,” under certain circumstances, he says. “Microphones are designed to detect and amplify almost unimaginably tiny vibrations in the air. A gust of wind, or even the faintest breeze, presents a gigantic signal to the microphone with predictably awful results. Foam windscreens dissipate that wind energy before it can reach the microphone [capsule], and are effective in direct proportion to their size.” Exhaled breath down from the nose and out the front and sides of mouth can be just as bad as wind, so it’s worth getting wind screens even for boom mics.Check the specsMicrophones have some of the most complete performance documentation of any pro audio product. These include information about sensitivity, directionality, RF rejection, signal-to-noise ratio, dynamic range, noise level and frequency response. This data can tell a lot about a microphone’s ability to fulfill a specific task and that, says Gabriel Antonini, new business development manager for DPA Microphones with U.S. offices in Longmont, Colo., is often overlooked by consultants when specifying microphones for a HOW sound system project. In fact, he adds, many microphones may never get an actual environmental test to listen to their characteristics in a similar environment. “Too often, the first time a microphone is heard is when a new system is being commissioned,” Antonini says. “The best way to decide which microphones work best for a project is to test them in a similar environment they’re expected to be used in, but the microphone’s data sheet can also give you a good idea of how it will perform.” For instance, he says, a microphone’s sensitivity is very important. “It reacts to the source SPL and if not matched properly it can compromise the integrity of the source signal being amplified and affect the integrity of the production,” he explains. “External noise or vibration is also worth investigating: microphones that are suspended from a truss or rafter can receive transmitted vibrations through the building structure, or vibration noise if it’s located near an HVAC unit or vent. Consultants should recommend the proper clips to prevent these scenarios before they happen.” Another resource he recommends is vendor support, for translating microphone performance data into practical applications in churches. “In my experience, it is always better to study the end result application and choose the mics that will capture the sonic detail accurately,” says Antonini. “Too often, the consultants specify a premium sound system and a premium mixing console, but [pay less attention to] microphones with the remaining budget. What they should be doing is ensuring that the first line of acquisition is a premium quality microphone that will transfer the intended sound to the console/sound system accurately.”Spectrum reallocation will be the big disrupter of the wireless portion of the microphone universe in the next few years, but it also serves to underscore the critical importance of good microphone choices of all types for houses of worship. Those are decisions that will increasingly start with AV consultants.
For more information and reproduction guidelines please contact us at 919-325-0120 or firstname.lastname@example.org (d1)