Race C4 Compressor/Limiter
By Jamie Rio
If one compressor is good, then four should be much better… right? Well, I think that more is better, and so does the R&D department at Rane. In reality, four compressor/limiters are not that many and can certainly be used in about any mix situation. But the C4 is much more than just four compressor/limiters. As a matter of fact, this frequency-dependent unit is loaded with lots of very cool and functional features. The Gear
At first glance, you will notice that the C4 has lots of knobs–40 in total, along with many toggle switches and LEDs. The device looks very analog, which worked for me considering my brain leans towards the analog side of everything. There are four identical units, which I also like because I only have to describe what 10 of those 40 knobs do.
The knobs are laid out in three rows. From left to right in the first row are the compressor threshold, ratio and gain knobs, plus the active/bypass toggle switch. Above that is a row of triple function LEDs that let you see what the compressor is up to at all times. The next row gives us the attack, release, knee and limit threshold, plus the headroom LEDs for the limiter.
This area also boasts an automatic feature, which is accessed by turning the release knob clockwise until the auto light is lit. This automatically sets your attack and release for most programmed material. However, unlike some other units with auto functions, you still have control over threshold, ratio, gain and knee.
But on the last row, we will travel right to left. Mainly because we have a very important toggle switch, which will allow us to select the compressor, de-esser or listen, and choose exactly what the detector hears. When listen is selected, the side-chain signal is routed to the channel output, which is very important when making PEQ adjustments.
And PEQ is the parametric gain, frequency and bandwidth knobs just left of the toggle switch. In compressor mode, the PEQ section operates like a regular second order filter with independent bandwidth, frequency and gain controls. Boosting or cutting a particular frequency makes the detector more or less sensitive to that frequency, and broadband compression still takes place. In the de-ess mode, the PEQ controls define a bandpass filter in the side-chain and a dynamic EQ in the main signal path. I don't want to get too technical with this description, so let me just say this section of the C4 is really fun to use at live gigs.
Before I address how the Rane unit performed in the real world of live mixing, let me first say a word about the Rane owner's manual. As part of my job as an FOH writer, I have to read a lot of manuals. Usually, they are a difficult read at best and absolutely indecipherable at worst. Not the Rane manual–I actually leaned some new things about compression and de-essing while I was checking out the overview of the C4 unit, so I want to give two thumbs up to whoever wrote it.
On With the Show
I arrived at the show a little late, so time was of the essence. My mission was to supply sound for a four-piece blues band. It would have been a walk in the park, but the lead singer also doubled on harmonica, and he used the same microphone for both vocals and harp. He also switched between electric guitars and a National Resonator that he played slide on. The National was a potential feedback nightmare.
There was also no sound check.
I started with the lead vocalist. I set the attack and release to auto, the ratio to 3-to-1 and the knee to soft. I figured I would set the compressor and limit thresholds once the lead vocalist started singing. But my real concern was when he started playing his harmonica. So, I adjusted the PEQ section, and I set my bandwidth to 1.5 octaves, frequency to 1.5kHz and left the gain at zero. This was all on the fly, so all additional tweaking would be done after the show began.
Next, I set up for the electric/resonator guitars. Once again, attack and release were at auto, ratio at 4-to-1 and I set the knee to the hard side of medium. I was again counting on the PEQ giving me some control over that hollow-bodied, resonator slide guitar. I put the bandwidth at 2 octaves, frequency at 1k and left the gain alone for the moment. I still had two compressors/limiter/de-esser left, so I set one up for the bass and one for a monitor mix. For the bass, I put attack and release on auto, compression at 4-to-1 and the knee to hard. In addition, I basically bypassed the PEQ.
For the monitors, I was looking at limiting the signal and controlling the potential for feedback. So I set the compressor threshold just under the limiter threshold, and I figured I would work the PEQ once we were underway. This entire setup took less than five minutes.
After the show started, everything was good. Not just in the ballpark, but in the infield of the ballpark. I of course made adjustments along the way, but the vocalist transitioned from singing to harmonica without hurting the audience, and he switched from electric guitar to slide resonator without any howling of feedback.
I think the PEQ section of the Rane C4 is the most useful feature. The entire unit is good and easy to operate, but the PEQ really helped smooth out the mix.
What is it: Quad compressor/limiter unit
What it's for: Anyone who does sound reinforcement
Pros: Feature-rich and they all work well
Cons: I really couldn't find any
How much: $999
Sennheiser e901 Boundary Layer Condenser Microphone
By Mark Amundson
At the winter NAMM show, Sennheiser debuted the evolution 900 series of microphones. While all the new offerings were impressive, the e901 boundary layer condenser mic really caught my attention. This is meant to be the answer to kick drum miking. The e901 has sculpted frequency response when in close proximity (~10cm) to the kick drum batter head, which significant notches out the low mids centered at 400Hz, and leaves much of the presence/high bands (2kHz to 20kHz) flat, as well as the critical 40Hz to 100Hz fundamental note response flat. So the e901 can be used as a one-mic kick drum solution instead of requiring a second large diaphragm dynamic mic to reinforce the low end. Also, the wide low frequency response permits the e901 to sound good to a wide range of batter head tunings and beater materials.
Taking cues from competitive offerings, the Sennheiser e901 ups the ante by incorporating both the condenser element preamp and XLR-male connector within the mic housing. Thus, there is no special cabling or in-line preamp that can be damaged during hard road use. In addition, the recessed connector means that the mating mic cable will not hinder mic positioning or the grip of the rubber bottom dampening plate pad on the e901. Overall dimensions are 5.05 inches by 4.13 inches by 1.05 inches, and weight 350 grams.
Diving into the specifications, the Sennheiser e901 offers the expected half-cardioid pattern response with a close proximity frequency response of 20Hz to 20kHz. Sensitivity is 0.5mV/Pa with a max sound pressure rating of 154dB SPL at 1kHz. The e901 requires phantom power, and at 48 volts, draws 1.1 milli-amperes of current.
Out at the gigs, the e901 showed its ruggedness by surviving a couple accidental drops and living up to its "step-proof" advertising. While I could just plug in the mic and flatten the channel equalization, I chose to be conservative and notch the mids a touch deeper. The resulting sound quality was perfect, and I had plenty of low end without having to reflexively grab the low frequency knob for a couple of decibel boost at 80Hz. And because all that high end is still there on the e901, I could choose, based on the genre of music or the song, to low-pass the presence and highs as desired. My conclusion on the evolution 901 microphone is that they got it right, and the word needs to get out on this kick drum "weapon."
What it is: Kick drum condenser microphone
Who it's for: Users seeking a tour-tough kick mic with simplicity of use and flexibility in sculpting a sound
Pros: Great mechanical styling, integrated preamp, neutral sound
Cons: None
How much: $379 MSRP
TC Electronic XO24 Speaker Management Controller
By Mark Amundson
TC Electronic has been known for highquality ambience and dynamic signal processing, but as of late has taken on the demands of live sound production and created some nice new gear aimed at our desires. In the digital speaker processor area, TC has entered with its XO24 model, known as a GPS for audio systems.
The TC Electronic XO24 Speaker Management Controller is a unique two-in by four-out signal processor that incorporates a signal flow diagram on the front panel and includes green LED illuminated push buttons at each process block to select and edit parameters of the selected block. While experienced speaker processor users will find familiar features like muting and channel selection buried in the buttons, unbiased "newbies" to digital speaker processors will find the operation reasonably intuitive.
Also on the XO24's front panel is the power push button and expected dual LED bargraph for monitoring channel A and B input signal levels. Note that scaling is per the input buttons, and choices of the trim level parameter are to full scale (clip) with zero to 24dBu values. The main display is a backlit two-row by 16-character LCD that conveys the parameter and value information per the context of the buttons. With no buttons flashing, the chosen preset number and name is displayed. The XO24 ships with 12 generic factory presets, and has room for 100 user presets for plenty of user flexibility.
After the display is the sea of buttons flow diagram that runs the analog/digital input select, input enable/trim, input parametric filters, signal routing, crossover filters, output parametric filters, delay lines, digital limiters and output enable blocks, in the two-in, four-out format. After the flow diagram is the normal TC Electronic interface for parameter control, including a value adjust encoder knob plus LED illuminated buttons for recall, store, enter, lock, edit, set-up and parameter up/down selections.
The backside of the TC Electronic XO24 Speaker Management Controller is pretty much minimalist I/O with six XLR jacks for the analog ins and outs. Two RCA phono jacks are provided for S/PDIF input and through connections, and a MIDI input jack is provided for a serial communication port for interfacing to personal computers for up- and downloading presets. Also provided is the much-beloved IEC input with a 100- to 240-volt AC input range. The internal switcher power supply is rated below 15 watts, so no major thermal output is expected from the XO24 circuitry.
Setup and Operation
The TC XO24 can be set up reasonably quickly if you avail yourself to the closest factory preset and start editing from there. Matching parameters from other speaker processors will be easy, but some value choices will be more coarse or fine depending on predecessor processor settings. I found that I was choosing slightly different values, but even coarser value selections were reasonable given the span of the values for the audio band.
In the relative comfort of my shop, I took settings derived for my EV XW wedges from EV/KT speaker processors and converted them into the XO24 settings with some effort; mostly the task was replicating high frequency and low frequency driver user presets four times each over the two XO24 units loaned to me, for four bi-amp wedge mixes. By taking both XO24s into edit mode, I could do parameter-to-parameter visual match-ups.
In Performance
I made the gigs a slam-dunk success with the XO24 speaker management controller by doing my shop homework, and by using my ears and real wedges for a non-time pressure assessment. Once placed at monitor beach, the pair of XO24s just hummed along and gave such pristine wedge mixes that the musicians complimented them. A couple things should be noted, and the first is the choice of output clip level. While the limiter default is the +20dBu level on the XO24, my amps limit at about +9dBu, so I had to re-think the XO24 limiter scheme, as opposed to just setting +9 for a limit value on other processors. The XO24 choices for output range are +20, +14, +8 and +2 dBu depending on professional or DJ audio level choices. So I chose the +14dBu output range setting and set the limiter values at -6dB for the LF drivers and -12dB for the HF drivers. This is a little awkward but useful.
My niggle list for the XO24 is short, but sums up in two competitive issues: mutes and output metering. As hinted earlier, the XO24 has no obvious input or output channel mute controls. The switches are there for enabling/disabling the ins and outs, but not made prominent via markings or illumination. My mind ponders the situation where suddenly a cable fault or drive line fault screams a 60Hz or other unintended audio down the input lines, and the system engineer has a scant second or two to make it go away. By having the mutes ready and available, little brain power is needed to guide the finger to the right buttons. And LED bargraphs for the four outputs would be a handy thing to trace or troubleshoot signal flows to the amps. It is one of those "at-a-glance" things that are reassuring to see dance on the front panel to show that all is well through the processor.
The bottom line is the TC Electronic XO24 Speaker Management Controller is very good to the signals, and modest in cost. While it took its own path in user interface ergonomics, it got most of it right to avoid the menu-select hell that most other processors offer. If you are a TC Electronic fan, and in the world of live sound, the XO24 is a good choice to add to your inventory. And if you are looking at other models and had not thought of TC in this context, the XO24 is worth a look.
What it is: Professional two-in, four-out digital speaker processor
Who it's for: Professionals who like the quality of TC Electronic signal processing and need a speaker processor
Pros: Pristine signal processing, easy to navigate user interface
Cons: No output channel metering or emergency mute indications
How much: $995 MSRP
Taylor Guitar Expression System
By Bill Evans
When I first told the publisher of FOH that I wanted to do this road test, he gave me the same look that is likely on your face right now. I know what you're thinking: "FOH is about pro-level live event audio. What's with a test of an acoustic guitar?" It's a legitimate question. Let's just say that the miking system that Taylor has dubbed Expression has the potential to make your gigs sound a lot better and make tour jobs a lot easier if you have to deal with acoustic guitar players.
Once upon a time, the only way to amplify an acoustic guitar was to stand the person playing it in front of a mic and pray that he or she did not move too much. Next, soundhole magnetic pickups appeared but they A) fed back and B) did not really sound like an acoustic guitar. Piezo elements under the saddle helped with the feedback and were the standard for a very long time, but they still don't sound like an acoustic guitar all that much. Over the past few years, we have seen hybrid systems that blend a piezo with an internally-mounted mic to bring back some real acoustic sound. They work, but feedback can once again be an issue.
The Gear
I first saw and heard (and started thinking about road testing) the Expression at Winter NAMM earlier this year. The system is standard on all Taylor guitars from the 300 series up and is, unfortunately, ONLY available on Taylors at this time (though they will retrofit some older Taylors). For this road test, they sent a very pretty red sunburst 612-CE.
The system uses what Taylor calls "sensors," which are basically contact mics that pick up the actual vibrations of the instrument instead of the air movements resulting from those vibrations. Two of these are mounted inside the body of the guitar, and the third resides in a pocket under the fingerboard where it joins the body. All three sensors feed an onboard preamp (designed by some guy named Rupert Neve), which comes out of the instrument as a–get this–balanced signal. The instrument ships with a cable that has a quarter-inch TRS to plug into the guitar and an XLR for the console. Yes, it plugs straight in without a DI.
There are three knobs on the guitar for volume, treble and bass control. And unlike most other systems, all of these are true boost and cut with a detent at the unity position and 12 dB of cut or boost. The tone knobs control shelving filters are centered at 125 Hz and 1 KHz. A standalone EQ box (also designed by that Neve dude) adds goodies, including a tuner output, both line-level TRS and mic level XLR outs, a phase switch, an effects loop and a fully-parametric mid band. I'm sure it's really cool, but with its chrome and wood case, it looked like something we were sure to scratch up beyond repair, so it was left at the shop. Truth is, while it adds some nice features, I never needed it.
The Gigs
When I first plugged the Taylor in, I figured it must be broken. I mean, when was the last time you had a plugged-in acoustic guitar sitting in a stand on-stage with the channel it's feeding wide open and you heard… nothing. It was so quiet that I had to call Taylor and ask if there was a gate in the preamp, which they swear is not the case.
Quiet is good, but the real revelation came when it was played. It sounds (could it really be?) like the very good acoustic guitar that it is. Turn the volume up or down on the guitar, and the tone is unchanged. And we really tried to get it to feed back, using it with a couple of pretty loud bands and nary a squeal was heard. Everyone who played it asked where they could get one.
As a sound guy or gal, if you work with acoustic acts, it is time to start dropping hints and get your artists to go with this system. If you own a sound company that does any backline at all, consider picking one up. It's a Taylor, so it's not cheap. But the outstanding sound quality, balanced outs, lack of noise and feedback make it worth every cent.
What it is: System for Taylor acoustic guitars
Who it's for: Anyone working with live acoustic guitars
Pros: Great sound, balanced outs, no noise or feedback
Cons: None
How much: $3,695 as tested, though price depends on guitar model because they're factory-installed
