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LA Lite CX2

Dual Channel Compressor By Paul White
Published December 1994

Paul White unpacks a crate of Lite and discovers a processor that could brighten up your rack as well as your sound.

Compression is one of the great philosophical paradoxes; legions of instrument designers strive day and night to create synths and drum machines with more dynamics and expressive potential than ever before, while their signal processing counterparts work every bit as hard to come up with new and better boxes to ensure everything comes out at exactly the same level irrespective of how it is played! Even the very wise have been known to ask why we don't just switch off the velocity sensitivity on our synths and cut out the middle man, but the practical reality is that while there's recorded music, there will always be a need for compression on vocals and acoustic instruments, even if only to compensate for the lack of perfect performance technique.

Green Piece

After having seen the tastefully lit ads for the LA Lites over the past couple of months, it came as something as a surprise when I opened the box to be confronted by a sea‑green rack case. Green might not be the most obvious colour for a piece of studio gear, but when you need to adjust it in a hurry, you'll certainly have no trouble spotting it in a rack full of black and grey boxes.

You might wonder why LA Audio felt the need to launch another compressor, when they already have the Classic, 4x4 and C4, but the idea behind the Lite range seems to be to draw on these earlier designs to provide low‑cost alternatives without sacrificing sound quality. Budget they may be, but the LA Lites still appear to boast the odd feature or two that most of the competition don't have.

I must confess to finding the CX2 rather attractive visually, and practically speaking, it's clearly set out. Power comes directly from the mains via an IEC socket on the rear panel (no wall warts on this baby), and the control knobs have clear marker lines and a nice, rubbery, tactile feel. Stereo jacks are provided for the inputs, outputs and side‑chain insert points. The ins and outs are balanced, and, as you would expect, the unit can be used unbalanced simply by plugging in an unbalanced jack lead.

A closer look reveals that some of the controls you might expect to find on a compressor are missing, and unlike the 4x4, the CX2 does not boast a built‑in gate. However, there is a filter section, which allows the CX2 to be used in split band mode, for tasks such as de‑essing or the creation of special effects. This aspect of the unit is obviously a spin‑off from the C4, and is an unexpected bonus on a compressor in this price range.

Interface

The compressor itself is a 'soft‑knee‑with‑ratio' type, making it well suited to unobtrusive dynamic control, such as might be demanded when compressing stereo mixes. However, it is still assertive enough to cope with all but the most erratic vocal line or instrumental performance. The usual Threshold, Ratio, Release and make‑up Gain controls are pretty much as you'd expect to find them, but in the place of the familiar attack control is a single button labelled Slow. With this switch out, the compressor has a very fast attack time (around 10 microseconds), which means that even the fastest transients are brought under control without overshoot. With the switch in, you don't get a fixed slow attack time (as you might reasonably have deduced from the legend), but instead, you flip to a programme‑dependent mode, where the attack time constantly adapts itself to the incoming programme material. This arrangement works extremely well on most types of material, and the only time you're likely to miss having a discrete attack control is when you want to set up a longer attack time to create deliberate overshoot — a popular technique used to add impact to percussive or plucked sounds. However, I have to say that the Auto mode works fine on most material of this type, and certainly doesn't lack impact.

A Bypass button links the input directly to the output, and a 9‑LED meter monitors the amount of gain reduction taking place (dimming in Bypass mode). A stereo Link button locks the two channels together for stereo operation. In stereo linked mode, both sets of controls still operate, but the side‑chains are fed with an average of the two channel settings, so it's best to set them up the same. For the record, I would have liked an output level meter to help me when setting the Gain control; this was undoubtedly omitted to save cost, but I'm sure a single 0dB LED wouldn't have been out of the question.

Falling For The Filter

The filter, which can be set anywhere from 100Hz to 10kHz, is where things get really interesting. With the Half button out, the filter is placed in series with the side‑chain signal, and because the filter can be set to high‑ or low‑pass operation, this facility can adapt itself to both de‑essing and de‑popping. With the Half button in, the filter acts as a 2‑way crossover, the frequency of which is set by the Filter control. With the LP switch out, only frequencies above the crossover point are compressed; if the LP switch is in, only frequencies below the crossover are compressed. (Compressing only frequencies above, say, 2kHz may help to de‑ess sibilant sounds unobtrusively in a situation where full‑band de‑essing might cause noticeable level dips.) In Split mode, the Gain control functions almost like a balance control, allowing the high‑frequency sounds to be balanced with the low‑frequency ones, and aside from being able to restore a reasonable spectral balance after compression, this also opens the door to a few creative tricks. For example, you could compress only frequencies above 5 or 6kHz, crank up their level slightly, and simulate an exciter. You can also use the CX2 as a single‑channel, dual‑band compressor, which lends you still greater flexibility. This is made possible by a simple normalising system that feeds channel 1's output directly into channel 2 if no input jack is plugged into channel 2. With the compressors in series, the two filter sections may be used to apply compression to two different areas of the audio spectrum, by setting both Half switches in and both LP switches out.

One minor quibble; to disable the filter section (for full‑band operation), it is necessary to select either HP and set the filter to 100Hz, or LP and set the filter to 10kHz. I imagine that this ritual could easily be overlooked, and perhaps a switched Filter pot might have been a more obvious way of disabling the filter.

Summary

Whenever a 'cheap' spin‑off is launched, based on a respected range of products, there's always an inclination to look for an Achilles heel, but in the case of the CX2, the only obvious compromise is in the metering section, where output level metering has been ditched in the pursuit of fiscal economy. LA have also fallen into their old habit of not labelling the switches as clearly as they might. As it is, the front panel tells you what you get when the buttons are pushed in, but not what they do when switched out.

I have no doubt that the circuitry has much in common with the C4, and like that compressor, the CX2 has a warm, musical sound which can be very flattering when used sensibly. The lack of an attack control isn't really a problem, and don't let the fact that the paint job is greener than a packet of Linda McCartney's Broccoli Surprise put you off!

The bottom line is that while there are inevitably a few minor compromises, the CX2 is an easy‑to‑use, musical‑sounding compressor that works well in most applications, including stereo mix processing.

Brief Specification

  • Inputs Balanced/unbalanced jacks, +18dB max
  • Outputs Balanced/unbalanced jacks, +18dB max
  • Threshold ‑40dB to +20dB
  • Release Time 20mS to 4S
  • Ratio 1:1 to 20:1 (soft knee)
  • Gain ‑12dB to +24dB
  • Filter 100Hz to 10kHz

Squeeze Me Please Me: Compression Fun

The CX2's split band compression is useful for de‑essing, but I'm reluctant to use split‑band compression on a stereo mix, except in a very subtle way (such as simulating an exciter by compressing only above 5kHz) as it's too easy to upset the spectral balance and to introduce unwanted phase shifts. It's a different story on individual instrumental sounds though, especially synthetic ones, because that's one area where you can afford to experiment without worrying about whether the result sounds natural or not. I also had lots of fun trying the split‑band option on acoustic guitar and vocals, where you can, for example, leave frequencies above 5kHz uncompressed, enabling the rest of the sound to be compressed quite heavily without loss of the high‑frequency detail. I also tried compressing just the lower 500Hz or so of an acoustic guitar track, which helped tame any tendency towards boxiness without choking off the high end.

Pros

  • Good audio performance.
  • Versatile split‑band mode.
  • Easy to use.

Cons

  • No output level meter.

Summary

An impressively flexible and professional‑sounding unit at a budget price.