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AKG DMS800 // List Price: From $2599
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(left) Samson Synth 7 // List Price: $444.99 & (right) The Shure QLX-D // List Price: from $999
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Sennheiser Evolution D1 // List Price: from $799
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Sony DWZ // List Price: from $499
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CAD Audio WX-100 // List Price: $508
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9. PreSonus // PreSonus’ line of StudioLive AI-series loudspeakers.
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(left) Mipro ACT 828 // List Price: unavailable & (right) The Nady U-800 // List Price: $279.99
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BeyerdynamicTG 1000 // List Price: Unavailable
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Electro-Voice RE2-PRO // List Price: unavailable
Selecting wireless microphones for your worship sound reinforcement system can be viewed as both easier and more difficult than it has ever been.
Easier in that the equipment available at a relatively modest price is typically more immune to interference, able to find clear spectrum on its own while operating over a wider frequency band, and more transparent in its transmission of audio signals. Yet potentially more difficult because of the changing wireless landscape, as the FCC considers “reallocating” wide swaths of radio spectrum and myriad wireless devices and applications compete for that spectrum.
The most significant question mark involves the Incentive Auction of Television Broadcast Spectrum, intended to encourage broadcasters to vacate most of the 600-MHz UHF band so that it can then be licensed for a variety of broadband applications. The planning and debate that will lead at some point to the actual spectrum auctions have been ongoing for the past several years, and is still in process. However, in the longer run, operating wireless mics in the reallocated bands will no longer be possible – similar to what happened when the 700-MHz band was vacated. So what are the possible solutions?
Key Innovations
Here’s the point where the more recent innovations from various wireless manufacturers come into play. These breakthroughs can be found in many analog as well as digital wireless systems, and include frequency agility over a relatively wide spectrum, receivers that actively scan for clear spectrum, more robust interference-prevention methods, and transmitters and receivers that communicate with each other during use. There are many benefits that arise from the newer digital wireless offerings—which typically incorporate all of the above features and more.
Most of the major wireless manufacturers currently offer digital wireless systems, meaning that the sound waves entering the microphone are converted within the transmitter to digital data, transmitted to the receiver, and then converted back to an analog audio signal (or with some of the professional touring systems remaining in digital audio format until it is converted to analog at the console output or within the amplifier/loudspeaker). Depending on your requirements, digital systems that operate in the UHF, 900-MHz, and 2.4 GHz frequency bands can be purchased—while the analog systems can be found in the VHF and UHF bands. Many of the technologies found within these systems are derived from the advances in telecommunications such as smartphones and high-quality audio algorithms, computer networking and wireless broadband, along with digital signal processing and audio networking.
Digital Advantages
Digital wireless offers a number of advantages. Digital transmission requires a lower signal-to-noise ratio in order to deliver a usable signal to the receiver, compared with analog wireless. As well, the signal is either on and with undiminished audio quality, or off and silent. “Noising up” and other audio artifacts are rare with these mics. Typically, a lower transmission power is necessary from the digital system’s transmitter compared with an analog unit to cover a similar distance. Many digital transmitters offer selectable lower and higher RF output levels depending on how far the users are from the receivers, and the congestion of the RF environment. Digital systems are more spectrally efficient, so that more channels can be used within a given amount of available spectrum.
As a rule, digital wireless systems have a wider audio bandwidth, at both ends of the spectrum, than analog, although some high-end professional analog wireless boasts excellent frequency response. A good analog system may have a response from 50 Hz to 15 kHz, while the digital ones are close to flat from about 20 Hz to 20 kHz. The responsiveness to the dynamics of the voice or musical signal with digital transmission is also generally broader and more accurate. Digital systems don’t require companding circuitry to compress and re-expand the original signal between the transmitter and receiver, with its potential to affect the audio quality. From my listening tests using these systems with voice and instruments, I’ve found the audio to be quite accurate and uncolored, even with the entry-level wireless.
Digital wireless systems do exhibit some degree of latency, since the conversion from analog to digital at the transmitter and then back again at the receiver does take a bit of time to occur. This latency is typically quite low and unnoticeable even when performers are listening to themselves through in-ear monitors – usually ranging from less than 3 ms to 5 ms. On the other hand, analog systems have zero latency, since there is no format conversion of the signal within the transmission. The range of most digital systems is sufficient for almost all applications, though some analog systems can potentially have a greater range, with the possible tradeoff of some signal degradation at the limits of their distance.
Making a Choice
As you consider new wireless systems, look into frequency-agile units that are tunable across a fairly wide swath of spectrum, so that you will have a good chance of finding clear spectrum even as the RF environment changes. For the UHF band, select higher quality systems that are more efficient with spectrum and resistant to interference. For longer-term use, as the spectrum auction comes to fruition, it may be best to choose systems that operate below 600 MHz. If you already are running several channels in the UHF band, consider filling in with digital wireless systems operating outside of that band, including 2.4 GHz and 900 MHz systems. And keep higher quality VHF systems in mind.
The most significant question mark involves the Incentive Auction of Television Broadcast Spectrum, intended to encourage broadcasters to vacate most of the 600-MHz UHF band so that it can then be licensed for a variety of broadband applications.
Even with all of the capabilities inherent in newer wireless systems, users must remain aware of the wireless environment, including potential sources of interference such as DTV, broadband, other wireless equipment already in use, and so on. Learn about which RF bands in your area are currently allocated and which are open, and become aware of which spectrum is likely to be auctioned for wireless broadband or similar uses. In larger installations, you may need to do frequency coordination, and know when you’ve reached the limits of channel density for a given frequency band.
And when you’re selecting wireless systems, keep in mind that the “wireless” part is how the signal gets from the mic to the console, analogous to a microphone cable in many ways. Although the transparency of that link will have an effect on the audio end result, the quality and performance of the mic element itself will be the dominant element. So check out how they sound as microphones, and opt for better quality.
Of the recent wireless offerings from a variety of manufacturers, the majority are digital systems, operating in either the UHF or 2.4 GHz bands, while a few are analog. Most are frequency-agile and function across a wide band of spectrum. Some have features such as digital outputs and the ability to network and remotely control them, which can be useful for larger, more complex applications.
AKG DMS800:
Transmission is digital, with a 24-bit/44 kHz sampling rate, and an audio bandwidth of 25 Hz to 20 kHz (+/-3 dB), and with 512-bit encryption. The system operates in the UHF band, offering two splits with a receiver bandwidth of 150 MHz. AES/EBU and Dante digital outputs, plus analog outputs are provided, with two receivers in 1RU; the receiver has scanning and spectrum analyzer functions. Variable transmitter power ranges in four steps from 10 to 50 mW. The HUB4000 network controller and HiQnet software allow networking and control. AKG also offers the digital 4-channel DMS-Tetrad receiver and related transmitters, operating in the 2.4 GHz band.
Audio-Technica System 10 Pro:
Transmission is digital, with a 24-bit/48 kHz sampling rate, and an audio bandwidth of 20 Hz to 20 kHz. The system operates in the 2.4 GHz band. The system self-selects clear frequencies, and via bi-directional communication between receiver and transmitter, will automatically change frequencies when interference is detected and coordinate those changes with other systems. It uses a combination of frequency, time, and space diversity technologies for reliability, and up to ten simultaneous channels may be used. Transmitter power is 10 mW.
Audix RAD 360:
Transmission is analog, operating on two 24-MHz splits in the UHF band, with 193 switchable frequencies per band. The half-rack, true-diversity receiver features RF scanning capability and the ability to select compatible frequency groups. Transmitter RF output is 50 mW. The handheld transmitter features interchangeable mic heads, and the bodypack transmitter accepts a variety of lavalier and headset.
Microphones Beyerdynamic TG 1000:
Transmission is digital, with a 24-bit / 44 kHz sampling rate, and an audio bandwidth of 20 Hz to 20 kHz. The system operates in the UHF band, offering one split with a receiver bandwidth of 319 MHz. Analog outputs are provided, with two receivers in 1RU; the receiver has scanning functions. Transmitter power is switchable between 10 and 50 mW. Switchable encryption is incorporated in the transmission. Networking is IP-based, using proprietary Chameleon software, and can be monitored and controlled from computers, tablets, and smart phones.
CAD Audio WX-100:
Transmission is analog, operating on one 20-MHz split in the UHF band. The system is frequency-agile, and up to 11 channels may be used simultaneously. The audio bandwidth is 25 Hz to 15 kHz. Transmitter output is 50 mW, and the system exhibits considerable range (over 500 feet in my own testing). Handheld, bodypack, and full-featured desk-stand transmitters may be paired with the receiver. Each receiver is half-rack sized, and two may be rack-mounted side-by-side. An antenna distribution amplifier is available, which supports up to four channels of wireless.
Electro-Voice RE2-PRO:
Transmission is analog, with an audio bandwidth of 50 Hz to 15 kHz (+/-2 dB). The system operates in the UHF band, with two 28-MHz splits available. The half-rack, true-diversity receiver features RF scanning capability and the ability to select compatible frequency groups, with analog outputs. Transmitter power is switchable between 5 and 50 mW for the beltpack, and is 30 mW for the handheld.
Line 6 XD-V75:
Transmission is digital, with a 24-bit / 44 kHz sampling rate, and an audio bandwidth of 10 Hz to 20 kHz (+0/-2.5 dB). The system operates in the 2.4 GHz band, offering one split with a receiver bandwidth of 75 MHz. The half-rack receiver provides scanning and selection of compatible frequencies. The diversity scheme includes both spatial and frequency diversity, with each transmitter sending out the same signal on two different frequencies. Transmitter power is switchable between 3.3 and 10 mW. Up to 12 channels may be used simultaneously. Transmission is encrypted, and both the handheld and bodypack transmitters incorporate EQ and microphone capsule modeling.
Mipro ACT 828:
Transmission is digital, with a 24-bit / 44 kHz sampling rate, and an audio bandwidth of 20 Hz to 20 kHz (+0/-2 dB). The system operates in the UHF band, offering several splits between 480 to 760 MHz with a receiver bandwidth of 64 MHz. SPDIF digital and analog outputs are provided, with two receivers in 1RU; the receiver has scanning and channel selection functions. Transmitter power is switchable between 10 and 50 mW. Ethernet ports are included for networking, using proprietary RCS2.Net software to control up to 64 channels. Switchable 256-bit encryption and receiver EQ presets are provided. Mipro also offers the ACT 24 digital wireless system, operating in the 2.4 GHz band.
Nady U-800:
Transmission is analog, with an audio bandwidth of 30 Hz to 18 kHz (+/-3 dB). The system operates in the UHF band offering two splits between 470–510 MHz with a receiver bandwidth of 20 MHz. The system provides auto-scan capabilities, with a pre-coordinated frequency groups and the ability to select any of 800 frequencies per split, and supports up to 14 simultaneous channels across the two splits. The half-rack, true-diversity receiver pairs with a selection of handheld and bodypack transmitters. Transmitter output is 25 mW.
Samson Synth 7:
Transmission is analog, with an audio bandwidth of 50 Hz to 15 kHz. The system operates in the UHF band with three 28-30 MHz splits available, starting at 518–547 MHz, with the others in the low and mid 600-MHz band. The half-rack, true-diversity receiver offers automatic frequency scanning with a spectrum analyzer display and is frequency-agile, with 100 available channels across the receiver bandwidth. Handheld and bodypack transmitters are available, with an RF output of 10 mW. Up to 20 channels may be operated simultaneously across the various splits.
Shure QLX-D:
Transmission is digital, with a 24-bit / 48 kHz sampling rate, and an audio bandwidth of 20 Hz to 20 khz (+/-1 dB). The system operates in the UHF band, offering nine splits between 470–937 MHz (country-dependent) and a 64-MHz receiver bandwidth. Up to 17 channels may be operated simultaneously per 6 MHz television channel spectrum. System latency is <2.9 ms. A variety of bodypack and handheld transmitters are available, with interchangeable mic heads, and a selectable transmitter output of 1 or 10 mW. 256-bit AES encryption is included. Remote monitoring and control via iOS devices is possible using the ShurePlus channels app.
Sennheiser Evolution D1:
Transmission is digital, with a 24-bit/48 kHz sampling rate, and an audio bandwidth of 20 Hz to 20 kHz. The system operates in the 2.4 GHz band, offering one split covering the entire band. The half-rack receiver provides continual RF scanning and selection of compatible frequencies, and features audio processing such as a low-pass filter and seven-band EQ. The system transmits on a selected frequency with the ability to switch to a compatible backup frequency when interference is encountered, and up to 15 simultaneous channels may be operated. Interchangeable dynamic and condenser mic capsules are available for the handheld transmitter, with automatic mic sensitivity adjustment based on the current level of the audio source. The systems may be controlled via Android and iOS applications.
Sony DWZ:
Transmission is digital, with a 24-bit/48 kHz sampling rate, and an audio bandwidth of 10 Hz to 22 kHz. The system operates in the 2.4 GHz band, offering one split covering the entire band. Two selectable transmission modes are available, using wideband or narrow-band frequency hopping technology. The half-rack receiver features a 5-band EQ and an intelligent feedback reducer, and has detachable antennas. Bodypack and handheld transmitters are available, with interchangeable dynamic and condenser mic heads for the handheld. A separate guitar receiver is available in a foot-pedal format, and includes a tuner with output muting, cable-length emulation, and powering via pedalboard power, 9-V battery, or external power supply. Transmitter output is 10 mW.
