JoeMeek C2

Is it really possible to produce a worthwhile stereo compressor which sells at under £200? Paul White finds out.

Bright green JoeMeek compressors have been popping up in studios all around the world over the past few years, but the C2 is the company's first low‑cost, dedicated stereo unit. Housed in the same case as their VC3 voice channel, the C2 uses the same photo‑electric gain‑control element as previous JoeMeek devices, but the way in which it is employed is slightly unusual. Designer Ted Fletcher has, in effect, reversed the 'mid and side' microphone principle by using a sum and difference circuit to split the stereo signal into a mono centre component and a 'side' difference signal. These are then compressed separately (controlled by a single side‑chain signal) before being rematrixed into regular stereo. The main advantage of this approach is that the left and right channels will always track evenly — compressing the left and right channels separately in the usual way relies on the gain‑control circuits being very closely matched, and while VCAs can be matched with great accuracy, I suspect that life isn't so easy when you're dealing with photo‑electric components.

There's nothing overtly fancy or complicated about the C2 — the ins and outs are on balanced quarter‑inch jacks and there are no side‑chain insert points. Mono operation is possible using the left channel on its own, but it is envisaged that most users will be processing stereo subgroups, full stereo mixes, or the outputs from stereo instruments such as samplers.

On the control front, there are knobs for Input Gain, Compression, Attack, Release and Output Level, as well as a bypass switch. There's no ratio control, as the soft‑knee design automatically increases its ratio as more compression is applied. Four amber LEDs show the amount of gain reduction taking place, up to a maximum of 16dB, while a second nine‑section LED meter shows the signal level after compression but before the output level control. A blue LED shows when the compressor is operational, while the top (red) LED on the level meter indicates that you're getting close to clipping. I called Ted Fletcher to ask him why he didn't include an auto attack/release mode and he explained that his attack/release circuit design incorporates a degree of programme dependability anyway — it's just that he doesn't mention it in the manual. The way it works is that fast transient sounds are given a faster release time, while sustained sounds behave as per the Release control setting.

On the whole, the C2 is easy to set up, it sounds consistently good and it's remarkably cost‑effective.

Technically, the C2 is capable of handling the 'hot' levels from the analogue outputs of digital recorders (the maximum input and output level is +28dB), but at the same time it has up to 26dB of available gain for when it's working with lower level sources. The quoted 118dB signal‑to‑noise ratio is better than most digital equipment can offer, and a nice touch is that the audio level stays nominally the same regardless of how much compression is applied, so when the bypass switch is operated meaningful A/B comparisons can be made between the bypassed and compressed sound.

The compressor section automatically varies its ratio from less than 2:1 to over 10:1, depending on the setting of the compression control and the level of the input signal. The compressor attack is variable from 1mS to 11mS. Release is variable from 250mS to three seconds, but the control law of the compressor is actually quite non‑linear during the attack and release phases. Far from being a bad thing, this characteristic non‑linearity combined with a degree of overshoot is what gives this optical compressor design its smooth, musical sound, but it also means you can't rely on using the compressor as a foolproof peak limiter, for example, when recording to DAT. You still need to leave yourself adequate headroom or employ a separate fast peak limiter. Distortion plays little part in tonal shaping as it is generally less than 0.01 percent, rising only when very low‑frequency sounds are being processed.

Compressing the left and right channels separately in the usual way relies on the gain‑control circuits being very closely matched, and while VCAs can be matched with great accuracy, I suspect that life isn't so easy when you're dealing with photo‑electric components.

Using The C2

Power for the C2 comes from the included low‑voltage power adaptor, and once this is plugged in, the unit is ready to go. I tried the C2 with various types of programme material, from solo instruments to complete stereo mixes with very obviously different things going on in the left and right channels. With instruments such as basses and acoustic or electric guitars, its possible to use the C2 as an effect to enhance the attack of the instrument or to warm the sustain, and if you set a very fast release time, you can also get it to pump nicely. I was, however, surprised at how transparent it can be made to sound on complex mixes, even when quite a lot of gain reduction is being used — voices can be evened out without noticeably changing their character, and often the only way you can appreciate how much gain reduction is taking place is to look at the meters. The stereo image also remained rock solid, so the M&S trick obviously works.

Summary

If you don't need a mic input stage, the C2 makes a useful general‑purpose compressor, as it can be used via an insert point to liven up mono signals, or you can patch it across your entire mix for global warming. It has the same musical sound as the other compressors in the JoeMeek range, and because of the clever M&S approach, the stereo imaging remains stable at all times. I like the way the output level is automatically stabilised as the amount of compression is changed, and because there's no separate ratio control, operation is very simple. It also inspires confidence that the balanced inputs and outputs can handle such a wide range of signal levels. On the whole, the C2 is easy to set up, it sounds consistently good and it's remarkably cost‑effective. You could spend well over £200 on a more impressive‑looking compressor covered in knobs and lights, only to find out that it is harder to operate and doesn't sound nearly so musical.