Arturia Synthx V

The latest addition to Arturia’s ever‑growing range of vintage instruments is a recreation of the celebrated Elka Synthex.

Despite its good looks and pioneering use of DCOs, the Elka Synthex was an eight‑note polysynth with an underlying specification that wasn’t unusual in the early 1980s, albeit with more flexible filtering and some interesting tweaks. It was a massive commercial flop and, despite its adoption by players including Jean‑Michel Jarre and Keith Emerson, it came and went almost unnoticed. Yet its reputation has soared over recent decades, turning what was a £400 ugly duckling in 1985 into a £10,000 swan in 2025. So this month’s question is not just whether a soft synth of a failed polysynth can replace the original, but whether it was worth developing in the first place.

The Sound Of The ’80s?

You could play the Synthex in what we would nowadays call Whole mode or using two layers that you could direct to the stereo outputs as separate synthesizers. Each voice was based on two DCOs that offered sync, ring modulation and an unusual cross‑PWM capability, a noise generator, a multimode resonant filter and dual ADSR contour generators. Modulation was provided by a single LFO per layer plus a global LFO for vibrato and wow, while a chorus effect helped to create lusher tones than would otherwise be possible. A basic sequencer completed the specification. A very rudimentary MIDI capability was added to later units, and a retrofit was available for earlier ones.

At first glance, the top panel of Synthx V looks much like a clone of this but, inevitably, there are differences, some in layout and more in function. Examples of the former include replacing the oscillators’ octave selection buttons with five‑position knobs, and moving the Sync button from the now‑defunct Tuning panel to the Oscillator 2 panel. Nevertheless, there are many additions. For example, where there were four filter modes and a contour polarity button on the original, there are now five filter modes and the polarity is taken care of by a bipolar Amount knob. This has allowed Arturia to sneak in a 12dB/oct low‑pass mode, and very welcome it is too. Similarly, there’s an extra knob in each of the Envelope panels, and these determine each contour’s velocity sensitivity.

By far the greatest number of changes on the front panel relate to modulation. While retaining the underlying structure, each layer’s LFO now offers a random waveform, sync and, most significantly, the inappropriately named Reset function which turns the per‑layer LFO into a per‑note LFO. There’s also an extra destination (pan) for the Depth 2 modulation path. Elsewhere, the LFO 2 section sees some significant changes. Most obviously, the joystick of the original has been replaced by pitch‑bend and modulation wheels, but if you prefer to use a two‑dimensional controller, you can still map its CCs to the appropriate destinations. Clock sync has also been added, and PWM, audio gain and pan have been added to the available destinations. Oh yes... and the Performance/LFO 2 settings weren’t saved on the Synthex, but they are in Synthx V, which is a Good Thing.

The Synthex’s unusual Glide/Portamento section has been retained, but Glide can now be applied to the filter cutoff frequency as well as the oscillator pitches. Glide is what was sometimes called Slalom in the 1970s; an upward or downward sweep from a predetermined offset to the pitch of the note played, and this makes it possible to obtain the usual range of hard‑sync screams. I find the dedicated contour to be far too linear, but you can use the modulation generators in the Advanced section (which we’ll address in a moment) to produce much nicer results.

Although the Synthex offered a Double function that placed two voices under each key, it lacked unison. In contrast, Synthx V offers three unison modes and your choice of key priorities when playing a layer as a monosynth. You can now stack five voices per layer with user‑defined detune, or retain either four‑ or eight‑voice polyphony on layer B, which is streets ahead of the original.

In addition to the Hold button (which has migrated from a now‑defunct Envelope Controls panel) the new Master panel includes a Vintage knob, which allows you to inject some uncertainty (or ‘dispersion’) into the oscillator pitch...