Anyone who has spent much time in the live sound world is no doubt familiar with the Crest name. Crest has earned a reputation as a manufacturer of top-quality permanent install/touring mixers, amplifiers, and various other audio products. Although the company is best known for large-format consoles, Crest is now turning its engineering expertise towards smaller mixers. Its XRack series of rackmount mixers is an example of this, offering an impressive feature set in an ultra-compact package.
The Crest XRM (List Price: $1820) is a 20x12 monitor mixer, joining a pair of smallfootprint stereo mixers in the X-Rack line. The XRM's 20 inputs are configured as 12 mono channels and four stereo pairs; these feed 12 output channels to provide up to 12 discrete mono monitor mixes. Through some clever routing controls, however, the XRM becomes a mono/stereo chameleon. You can pair up any two adjacent output channels for stereo operation, and the XRM's stereo inputs can also function just like standard mono inputs.
Ins and Outs
All inputs on the XRM offer XLR and 1/4- inch balanced connectors, a mic/line
preamp with up to 70 dB of gain, individually switchable phantom power, an
insert point, and a passive split output to continue the signal on to the front-ofhouse
mixer. The XRM's input scheme is quite clever--with both 1/4-inch and XLR signals
connected, a top-mounted line input (Mic Pad) switch selects between the two
input signals. With only an XLR jack in place, the switch engages a 26 dB pad
on the mic signal. Use line-in only, and the 26 dB pad is on by default.
Once through the input stage, the 12 mono inputs hit a switchable high-pass filter (18 dB/octave at 70 Hz) to eliminate low-frequency noise such as stage rumble or wind buffeting. All channels then move through the XRM's four-band EQ. This EQ offers high and low shelving filters as well as sweepable low-mid and high-mid filters. An "EQ On" button allows you to defeat the EQ if desired.
Next up is the master channel fader, which allows overall adjustment of the channel's signal(s) in all mixes. This control is actually optional for a monitor mixer, as across-theboard changes in level can be easily accomplished with the input trim control. That said, the master fader is a nice touch. A PFL (prefader listen, or solo) button sits near each master fader, as does a signal level/peak LED and mute switch with LED. The channel signal/peak indicator glows brighter green as the signal level increases, switching to bright red when the channel is within 3 dB of clipping.
After the master fader are the XRM's 12 output level controls. These knobs function identically with one exception: a switch at the top of the "Mix Sends" section sets sends one through four to the pre master fader. This switch is useful when you don't want outputs one through four to change with the master fader level (for recording from the monitor board, for example). Knob colors and mixer graphics organize mix send knobs in pairs, for reasons that point back to the mono/ stereo flexibility of the XRM.
On the far right side of the XRM is the output section, which has a 60 mm fader, solo button, signal/peak LED and low-cut switch for each of the board's 12 outputs. The low-cut filter on the XRM's outputs offers the same steep slope as the input filter (18 dB/octave), but at a much lower 40 Hz. Each pair of output channels also has a "Stereo Pair" button that converts the pair to stereo operation. This tells the XRM that it's time to change colors, reconfiguring both the output pair and the function of every channel's mix send knobs for that pair.
When switched to stereo mode, each channel's odd-numbered mix send knob for that pair becomes the stereo send level control, and the even-numbered knob becomes pan. In the case of stereo inputs routed to stereo outputs, the first knob of each pair of controls level, while the second becomes stereo-balance (instead of pan).
Above the main output section sits the XRM's monitor controls, including a headphone jack with level control, solo LED that lights when any input or output is soloed, and a 12-segment meter that shows the level of the soloed signals. Near the headphone output and level control sits a "Speakers On" switch, which sends the output of the solo bus to a pair of XLR or 1/4- inch balanced speaker outputs. In addition to headphones, monitor engineers often set up a wedge monitor or two (or even studio nearfield monitors) to listen in on their mixes. The XRM is set up nicely for this.
At least one more feature on the XRM-- "Common Input"--is worth mentioning. This stereo input (XLR or 1/4-inch balanced) feeds all output mixes, and a single knob controls its level in all mixes. If all musicians and vocalists need to hear a backing track, effects return, or click track, this is a tidy solution that doesn't use up a precious mono or stereo input.
In-Ear or Out
Many churches and other live sound venues are moving to in-ear monitoring systems,
and the XRM is perfectly equipped for this application. The board will generate
six stereo mixes, each with an insert point for patching in a brick-wall limiter
to protect hearing. If more mixes are required, you can easily drop some outputs
back to mono.
Whether driving in-ear monitors or traditional stage wedges, the XRM's performance is excellent. The board's sound is pristine. Along with impeccable frequency response, noise and crosstalk specifications, the XRM's phase response stays within +/- 30 degrees through the full audible spectrum. This is a very impressive performance--the XRM maintains a level of signal purity that a lot of analog recording equipment can't touch.
Crest's commitment to signal purity and flexibility affects all aspects of the XRM. Other than insert points, for example, every input and output on the XRM is balanced; every channel input offers both XLR and 1/ 4-inch balanced connectors. Individual ground lift switches on each input help eliminate noise from ground loops, another invaluable "clean signal" feature. Flexibility has its price, though--the XRM's bottom panel is awash in XLR jacks, 1/4-inch connectors and buttons. No cost-cutting compromises in this department.
Great sound quality wouldn't be much use if the board wasn't easy to learn or operate. Turns out the XRM is both, thanks to a very logical control layout and clear labels and graphics. Getting up-to-speed with the XRM should be quick and easy for even moderately experienced engineers, aided by the fact that the Crest manual is one of the best I've ever seen. If only every manufacturer produced manuals that were so informative and well written.
About the only operational challenge related to the XRM is the density of the control layout. This little mixer has a whopping 322 knobs on its front, and they're packed in pretty tight. Thankfully, the XRM's knobs are well damped and only move with deliberate effort. Buttons are also quite stiff, require ample travel, and change position with a definite tactile click. I never once moved a knob or switch by accident while using the XRM. I can't say the same of the mix output faders--these have too little resistance, and it takes some diligence to move just the fader you want.
I did find just one feature missing on the XRM, and it's not one everyone will need. The common input is pre-set for a +4 dB (professional level) signal source, while some applications will require feeding this input with a --10 dB (consumer-level source) such as a CD player or drum machine. The input will still work, but getting adequate gain could be a problem. A +4 dB/-10 dB switch for this input would have been a worthwhile addition. While we're wishing, a mono sum switch for this input would increase its compatibility with mono mixes.
In the grand scheme, these last concerns are completely overshadowed by the flexibility and quality of the Crest mixer. Thanks to impeccable engineering and a wellconceived feature set, the XRM is a class act from input to output. Whether using in-ear monitors or wedges, requiring rack-mount portability or not, the XRM will handle most monitor mixing chores with aplomb.
Kurt Gibson is a regular contributor to Church Production Magazine.
