The Shure ULX-D brings cutting-edge digital wireless technology with robust professional touring features and quality to the mainstream. For critical performance and broadcast applications, in settings with multiple wireless channels in a crowded RF environment, where maintaining a digital audio signal chain path from microphone through the console is desired, and when only the very best will do, the ULX-D is a fine choice.
The roadworthy 1-RU chassis with internal power supply holds two or four wireless receivers with practical front-panel controls. A half-rack, single-channel receiver is also available. Extensive application menus in both the transmitter and receiver offer a plethora of professional capabilities such as audio summing, bodypack frequency diversity for redundancy, scanning modes, and custom frequency groups. Other aspects of the ULX-D system include transmitter encryption, both Ethernet networking and Dante digital audio capabilities, and a very clean, transparent implementation of digital transmission.
Audio Quality
First of all, the Shure ULX-D system sounds quite good—the most important factor for the initial input into your sound reproduction system. With flat 20 Hz-20,000 Hz frequency response and no companding from the 24-bit digital audio stream, the result is virtually identical to using the wired version of the mic, retaining the transient response and the character of the particular microphone capsule. Comparisons using three different heads on the transmitter and the wired versions of the same microphone bore this out.
In an A/B comparison between the earlier Shure professional analog wireless, the UHF-R, and the new digital ULX-D, the audio response of the latter was full bandwidth and uncolored, and was an improvement in quality to the analog system. This opinion was confirmed by Kevin Windrem, owner of Sweet Spot Sound in Grass Valley, Calif., who knows his UHF-R well and was pleasantly surprised that the digital unit sounded better.
The ULX-D has an extremely wide dynamic range of greater than 120 dB through its analog outputs. This dynamic range is made possible by Shure's Gain Ranging technology within the transmitter, which optimizes the dynamic range for any input source from quiet to very loud. Gain Ranging eliminates the need for gain adjustments in the handheld transmitter (the bodypack does have a selectable 12-dB pad). Testing this capability, a shout did not clip the signal and a soft voice was reproduced with no additional noise. This innovation is completely transparent.
Each receiver channel has a gain control with a range of -18 dB to +42 dB, adjusted via front-panel controls within the audio menu or from a control computer when networked. Setting levels is straightforward, and the channel's audio LED meter provides additional visual feedback. A rear-panel mic/line switch provides a 30-dB pad, rounding out the system's gain staging.
Transmitter RF Output Levels
Transmitters can be set to three RF output levels—20 mW, 10 mW, and 1 mW. The specified operating range for the ULX-D is 100 meters (330 feet) for the 10 mW transmitter setting. Using the system's standard channel spacing of 350 kHz, up to 17 channels can operate within an open 6-MHz television channel.
In High Density mode, up to 47 transmitters may be squeezed into one 6-MHz television channel, at a spacing of 125 kHz apart. Shure specifies a working range of up to 30 meters using this mode.
Trying this procedure with the dual-channel ULX-D receiver, 470.125 and 470.250 MHz were presented, and the IR sync function passed those frequencies to the transmitters. The audio quality was just as good as with the standard channel spacing, and I was able to walk a considerable distance away from the receiver and still have dropout-free audio.
Scan and Sync
Several frequency bands are available, covering the range from 470 MHz to 932 MHz—some of which are specifically for use outside the United States. Many of the bands span 64 MHz, or more than 10 U.S. television channels.
Within each band, multiple sets of pre-coordinated compatible frequencies are provided across the tunable range of the receiver. For example, the 474-534 MHz “G50” band offers 25 frequency groups, and Group 1 contains 67 coordinated channels. The user also has the ability to set custom groups using a selection of frequencies and directly set each receiver to the chosen frequency.
When performing the scan operation during setup in a new location, especially when you will be using many channels of wireless, initiating a Group Scan finds the group with the most available frequencies. When the receivers are networked via Ethernet, the system will automatically assign the group and a compatible channel within that group to each receiver.
The actual syncing of transmitter to receiver is simple. Turn on the transmitter, press the Sync button on the desired receiver channel, hold the transmitter's IR window (right under the LED display) within six inches of the receiver, and it will quickly transfer the frequency and it's ready to use. The IR syncing is also used to transfer name labels and encryption from the receiver to the transmitter.
Noise-free Operation
Shure appears to have designed a wireless system that is very forgiving of mistakes such as turning a transmitter or receiver on or off with the audio channel still open—an action that in many older analog systems would result in an amplified pop or at least some undesirable noise. At cautious low levels at first, then at higher gain, I turned a transmitter on and off, as well as changing RF level settings and frequencies. No noise effects, other than the slight mechanical effect of the switch being touched, were detected—just silence. In addition, the transmitter goes from the off position to on and transmits audio in a fraction of a second.
Moving on to the receiver, flipping the power switch caused no pops or other noise, either on or off. When turning on, the receiver appears to stabilize for a few seconds, and then a relay triggers to open the audio output circuitry; the relay also sounds like it triggers as the power switch moves toward the off position.
Encryption
The ULX-D system allows Advanced Encryption Standard (AES-256) 256-bit encryption to be enabled when a secure wireless transmission is desired. The encryption is robust, fast-loading, and is transparent to the audio. It is found in Device Utilities > Encryption, and is easy to implement and set using the IR sync. If either the transmitter or receiver has a different encryption status, the audio is muted and a warning flashes on the display. All transmitters must be re-synced when encryption is selected, since all channels within the receiver chassis are affected.
Locking Controls
Both the receiver and transmitter controls can be locked to prevent accidental or unauthorized changes to system settings. On the receiver, Menu, Gain, Power, Scan/Sync capabilities can be locked via the Device Utilities menu. The handheld and bodypack transmitters have controls located under the battery cover to enter and select menu items, including the ability to lock Menu, Power, or both.
Networking
Multiple ULX-D receivers can be networked to provide real-time monitoring and control of the individual wireless channels using Shure's Wireless Workbench software. Networking also allows scanning and group/channel selection across all receivers, with the best available frequencies automatically allocated for the particular location. Wireless Workbench displays each channel's audio meters, transmitter parameters, frequency settings, encryption status, and other information. Adjustments can be made on the fly to gain, receiver channel muting, frequencies, RF power, audio summing, frequency diversity settings, and control locks.
Networked receivers can also connect to an AMX or Crestron control system, using the same Ethernet cables as Wireless Workbench.
Dante Digital Audio
The ULX-D is enabled for Dante digital networked audio using the receiver's rear-panel primary and secondary Ethernet ports. Thus the audio signal can remain in the digital domain without conversion to analog from the transmitter through the receiver, and to a digital mixing console or other devices. Dante allows the distribution of multiple channels of low-latency audio over a single Ethernet cable and can coexist with control data from Shure's Wireless Workbench software.
Antennas
The dual and quad receivers share one set of antennas per two or four wireless channels, with each unit having an A and B BNC antenna connection paired with a second BNC cascade port, allowing looping to one additional receiver. Setting the receiver to Antenna Bias provides DC bias current to power active devices, such as remote omni and directional antennas. The format of the ULX-D yields excellent receiver density for touring applications, with 16 receivers possible in a 4-RU rack, for example.
Replaceable Mic Capsules
As with Shure's other professional handheld transmitters, a variety of easily replaceable microphone heads are available, from the ubiquitous SM58 to the elite KSM9, as well as heads from other manufacturers conforming to Shure's threaded concentric-ring mating connection. This capability provides a great deal of flexibility in matching the wireless to the requirements of the performer or to the characteristics of wired microphones also being used.
Rechargeable Batteries
Transmitters run on either a pair of AA alkaline batteries or Shure's proprietary lithium ion rechargeable battery pack. The optional SB900 rechargeable battery provides 12 hours of transmission, and remaining time is displayed in hours and minutes. Batteries can be charged separately or in the transmitter.
Conclusions and Pricing
The Shure ULX-D is quite a technological achievement. Audio reproduction is natural and unaffected, controls and menus are well positioned and can be accessed quickly, and a host of capabilities from audio summing to encryption are offered. Receivers and transmitters are well designed and roadworthy, the system can be networked, and it can even output digital as well as analog audio signals.
Such quality does come at a price. A single-channel ULX-D with a handheld SM58 lists at $1,686, while a two-channel receiver with a beltpack/handheld Beta 87 combo is $4,475. If reliable, excellent audio performance is paramount, the Shure ULX-D will give the professional user all they could want from a wireless microphone system.
