Technology Showcase: Wireless-microphone Systems
Jan 1, 2008 12:00 PM, By Bennett Liles
The latest professional options offer serious “broadcast” capability.
The comment that wireless-microphone users were operating a radio station used to be fairly comical and quaint, but now that many wireless systems include transmissions of tones and telemetry, there is some serious broadcasting going on. Most professional equipment — including wireless IFB and in-ear monitoring systems — now uses pilot-tone muting, also known as tone squelch, to quiet receivers when transmitters are shut off. Battery-condition telemetry and other data signals have become common, as well. Dodging intermode and other types of interference has been automated, with computer-connected receivers trading data with their microphones. Digital transmission, encryption, and infrared wireless systems have also made their debut. Let's take a look at some of the latest products in the wireless-microphone realm.
The new AKG Acoustics D5 wireless-mic capsules introduced at InfoComm 07 are capable of operating with several AKG microphone systems, including the WMS 450, which is composed of the SR 450 receiver and the HT 450 handheld transmitter. Designed for rugged road use, the HT 450 can run for up to 8 hours on one AA battery, and it includes a spring-steel, wire-mesh cap. The microphone can be configured automatically from the receiver by IR link. The SR 450 has a programmable status display with a two-color backlight, a scanning function with a country-specific database, and a rehearsal function for finding dead spots. The WMS 450 D5 vocal set can be found for less than $800.
Anchor Audio offers the UHF 64-channel wireless system, which is composed of the UHF-6400 receiver, the WH-6400 handheld mic/transmitter, and the WB-6400 body-pack transmitter. Also available for the system are lapel, over-the-ear, and headband mics. The receiver includes group/channel-setting buttons, RF- and AF-level meters, volume control, and headphone output. On the rear panel are balanced-XLR and unbalanced 1/4in. output connectors. The transmitters are rechargeable from the receiver, and the WB-6400 transmitter has mic- and line-level switches and a low-battery indicator. Approximate retail prices on these are $310 for the WH 6400, $230 for the WB 6400, and $218 for the UHF 6400 receiver.
The Blue Class wireless system from Ansr Audio is a 700-channel set consisting of the AW-70 receiver; AW-2 or AW-3 transmitters; and AM-11, AM-14, AM-15, AM-16, or AM-17 microphones. The receiver front panel includes channel, frequency, and audio-level display; channel and volume-select switches; DC output for charging transmitters; and headphone output with volume control. The rear panel offers balanced-XLR and unbalanced 1/4in. audio output connectors and squelch control. The transmitters include a display showing channel and battery condition and channel-select switches located safely inside the battery compartment.
Audio-Technica has taken a new approach to using ultrawideband (UWB) technology with its SpectraPulse system, introduced this year. The system employs a digital transmission technique in which brief nanosecond pulses of data are sent over a 500MHz-wide swath of spectrum. In a multi-microphone scenario, each microphone has its identity in the system set in hardware and synchronized with a receiver taking its turn at transmission in a time-division-multiplex access method. An optional encryption package is available that meets the NIST-approved 128-bit encryption standard. One receiver unit can handle seven mics in one rack space, and it can be linked to a second receiver for a 14-microphone system. Each Mtu101 boundary-mic transmitter retails for $1,300, and each audio control interface is $4,600.
The RAD-360 frequency-agile UHF wireless-mic system from Audix offers 193 frequencies for simultaneous operation of 12 to 16 transmitters. Soft-key controls operate menu-driven LCD displays for programming, signal strength, frequency, A/B antenna indicator, mute status, RF indicator, battery level, and lock status. The RAD-360 handheld transmitters feature interchangeable heads, and the body-pack transmitter can be used with the ADX10 lavalier mic, the ADX20i condenser mic, or the HT2 headset mic. The optional ADS-4 antenna distribution system can run four receivers on one pair of 3/4-wave antennas. The various system configurations range from $650 to $750.
The Azden 320ULT dual-channel system is an on-camera wireless-mic model that consists of one 320UPR receiver and two 30BT body-pack transmitters with EX-503L lapel microphones. The receiver features a digital readout and separate power switches for each channel, an important feature with this battery-powered system. Batteries can be recharged internally, and power can be taken from an external source. The receiver includes dual-XLR and stereo-mini output connectors, a removable shoe mount, and flexible antennas. The transmitters have a digital readout showing frequency selection and battery level. The system MSRP is $995.
Introduced at NAMM 2007, the Behringer Ultralink UL2000B headset system has 320 selectable frequencies for operation of up to 20 microphones simultaneously. The IRC compander automatically adjusts the expansion ratio when the signal goes below a predetermined threshold. The LCD shows a menu brought up by the set button, and it displays frequency, channel, RF level, and mute status. The rear panel features XLR and TRS output connectors along with a ground terminal. The ULB2000 transmitter offers a multifunction power button, mute switch, value selection dial for programming, and a status LED that blinks with varying speed for different messages. The UL2000B system lists for less than $300.
The Opus 900 from Beyerdynamic — built around either the NE 900 D 2-channel, the NE 900 Q 4-channel, or the NE 900 S single-channel receiver — features autoscan and automatic channel targeting through an IR link to the microphones. Adjustable output level, squelch, and programmable user name add control to as many as 16 simultaneous transmitter/receiver pairs. These can be used with the TS 900C and TS 900M body-pack transmitters and half a dozen different Beyerdynamic handheld microphones. Prices vary significantly depending on specific system components.
The Clockaudio CW9000R receiver is part of a system that includes the CW9001T belt-pack transmitter and the CW9000T handheld transmitter, and one that offers diversity reception with twin receiver circuits and balanced and unbalanced outputs in an all-metal case. The belt-pack transmitter tunes to 192 phase-locked loop (PLL) selectable frequencies displayed on an LCD along with battery status. The transmitter also includes audio-level control and a power switch. The unit can run for up to 8 hours on two AA batteries. The CW9000T has the same features, and it can fit either a dynamic or a condenser head. It is rated to run for 10 hours on two AA batteries, and it uses an integrated dipole antenna.
The Electro-Voice RE-2 wireless-mic system features a receiver with Digital Posi-Phase diversity and a tone code plus an amplitude-squelch function. The backlit LCD shows AF and RF levels, frequency, battery level, and active antenna, as well as group and channel numbers. Auto-ClearScan finds the most interference-free channel among 1,112 available. The RE-2 UHF handheld transmitter can fit any of three mic elements for a choice among dynamic, condenser, and dynamic with vocal-optimized bass. Batteries fit only one way to ensure proper insertion in low-light conditions. The RE-2 body-pack transmitter includes optional pouches to match a wide variety of microphones. The set with both transmitters and receiver is available for less than $700.
Among the options for the UF-series wireless-mic system from Gemini Sound is the UF-8264 receiver with 64 selectable frequencies, a group/channel display, a power indicator, an RF-level meter, an audio-output-level knob, and a DC charging port for the transmitter. The rear panel includes balanced and unbalanced audio connectors along with a manual squelch control. The FM-64 handheld transmitter can be fitted with either a dynamic or electret-condenser capsule. With the power switch, the unit features an LED to indicate battery condition. The FB-64 body-pack transmitter uses a mini-XLR mic connector, and it has the same features as the handheld model. The system with both transmitters and receiver can be found for about $200.
Lectrosonics provides a high-security wireless solution in the versatile UDR700 encrypted digital UHF diversity receiver with phase-based Rota-versity reception, adjustable audio output level, AES/EBU and analog audio outputs, a headphone jack with volume control, a phase switch, a ground lifter, and the capability to manually switch to either antenna for testing. The front panel includes 10-segment LED RF-level and audio-level metering. Used with the UM700 body-pack transmitter and the UT700 handheld microphone, the UDR700 applies 24-bit A/D conversion, 44.1kHz sampling, and digital signal processing, and it uses a multi-stage encryption process with a 128-bit key. The UDR700 can be found for just more than $3,000, and the UM700 is available for around $1,200.
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