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Wersi MK1 Synthesiser

Polyphonic Synthesiser

Simon Trask follows up our earlier preview of Wersi's first polyphonic synth, with a full review that delves deeper into the possibilities of additive synthesis. Is it too complex to use?

When we first looked at the MK1, it overwhelmed us with a vast range of programming options. We've since played with it for longer, but will working musicians have time to do the same?

THE BIG JAPANESE manufacturers - Casio and Yamaha especially - have brought the synthesiser and the home keyboard closer together than ever. For them, the difference between a home keyboard and a synthesiser has now become one of how the technology is packaged, rather than what the technology actually is.

Which is fine for the sort of economic and marketing structures the Japanese employ, but not quite such good news for European companies - like Elka and Wersi - who have made a name for themselves as manufacturers of quality organs and home keyboards, but who now have to work at break-neck speed just to keep up with the Far East.

Elka are already well known for their diversification into upmarket synths with the renowned Synthex, and have now come up with the EK22 and EK44 analogue and digital synths (both reviewed in E&MM October '86).

And Wersi are now claiming their stake in the action with the MK1 polysynth (previewed in E&MM July '86), and they too have chosen to aim their sights upmarket. As such, it would be reasonable to expect a highly-specified instrument - which, as it turns out, is exactly what the MK1 is.

The Wersi comes in eight-, 12- and 20-voice versions. Lurking beneath its unprepossessing exterior are eight 'internal manuals' (the organ terminology makes its appearance pretty quickly), each of which can be looked upon as a polyphonic synth in its own right, with its own sound which can be selected internally or via MIDI.

Each "sound" on the MK1 can in fact consist of up to four components, each of which can be a sound in its own right and can be given its own volume level. Routing allows you to send each component/sound to left, right or both audio outputs.

The MK1's layering ability allows you to put together some very effective sound combinations. What's more, it's possible to link together pairs of manuals when playing from the keyboard, to allow even more components to a "sound". In fact, it's when you start layering sounds that the MK1 really comes into its own.


THE MK1 ALIGNS itself with other new synths such as the Prophet VS and the Kawai K3 by adopting the Additive Synthesis approach to sound creation, combined with familiar analogue filtering. Wersi have also included software-implemented effects processing (still something of a new technique), providing onboard flanging, chorusing, rotating-speaker effects, feedback, distortion and "strings" (the latter an "ensemble" effect).

Wersi have provided up to four different waveforms (imaginatively labelled "bass", "tenor", "alto" and "soprano") spread across the five-octave keyboard (which is sensitive to both velocity and pressure, by the way), an approach similar in principle to multi-sampling.

The bass waveform is active over the lowest two octaves of the keyboard, while the other three waveforms occupy an octave each. The bass and tenor waveforms can have up to 32 harmonics apiece, while the alto and soprano have up to 16.

The amplitude value for each harmonic (which has 12-bit resolution) can be set using 16 front-panel sliders. Starting from scratch, it's a laborious process just to define a sawtooth wave (which the manual - or perhaps I should say "user guide" - tells you how to go through). The route for most people will be to modify existing sounds through a combination of additive synthesis and the various sound-processing options that the MK1 has onboard. At present the sounds available for the MK1 aren't plentiful, but according to Wersi, several sound cartridges will be available imminently.

The current selection of sounds includes strings, piano, bass, organ, vibes, guitar, bells and brass - a reasonable selection to begin programming with.

The MK1 allows you to select a single floating split-point, with dynamic allocation of voices to each side of the split. Manual zero corresponds to the right half of the keyboard, and manual one to the left half.

To the far left of the keyboard are sliders for master volume, left volume and right volume (corresponding to each side of a split) and Balance/Solo/AOC. The effect of the latter depends on which function you have activated. Balance allows you to alter the volume level of each component in a sound (which, remember, can have up to four components); Solo allows you to adjust the balance of the top voice and the remaining voices in a chord; while AOC has a similar function in allowing you to adjust the volume balance between the played note and the other chordal notes that are automatically generated in the right hand on the basis of the chord played with the left hand.

Confusingly, the Wersi's voices are organised in three different groups, going under the guise of DMS Instruments, CV Instruments and Total Instruments.

DMS voices are presets in ROM (20 onboard, a further 20 on ROM cartridge), while CV voices are the same as DMS voices except that they are held in RAM (20 onboard, a further 10 on RAM cartridge) and can consist of a maximum two components compared to the DMS instruments' four. To make a four-component CV sound, you have to link two CV instruments together.

Total Instruments (16 onboard, a further eight on RAM cartridge) are equivalent to performance memories. So this is where you store split information together with volume settings for all voice components, touch-sensitivity and wheel settings, and such parameters as routing and tuning for each sound.

"Confusingly, the Wersi's voices are organised in three different groups: DMS Instruments, CV Instruments and Total Instruments."

The complete contents of a RAM cartridge can be transferred to the MK1's memory, into either upper or lower "banks", and either of these banks can similarly be transferred to cartridge.


ALL OF THE MK1's plentiful functions (and there are enough of them, believe me) are accessed through something called a Function Control Matrix, on the right-hand side of the front panel. This has six "levels" which are selected by pressing various combinations of buttons to the right of the matrix display. To see which parameters you are accessing on each level, you have to refer to a clip-on spiral-bound booklet (only the Play level is printed on the instrument itself); it's a far from ideal device on a professional instrument, and is bound to come unstuck (sorry) at some stage or another.

The Wersi's filter section allows you to select between low-pass and band-pass filtering, four-pole and two-pole cutoff, tracking frequency offset, and whether or not the VCF will be retriggered with each note. You can also define a two-phase frequency envelope with four frequency levels and adjustable time span.

Wersi have given the MK1's touch-sensitivity a healthy array of voice parameter assignments. Velocity can be assigned to VCF frequency (with a choice of three scales), volume and "voice" (the latter including attack time, release time, vibrato and detune), while aftertouch can be assigned to vibrato, volume, VCF frequency and pitch. The ranges within which these dynamic effects operate can be limited; in the case of velocity, you can define ranges for the whole instrument and for individual voices.

Assignability is also the name of the game with the MK1's performance controllers. Wheel 1, which is centre-sprung, can be assigned to control vibrato (up for frequency, down for amplitude) and/or pitch-bend. Wheel 2 can also be set to control pitch-bend and vibrato, along with any of VCF frequency, VCF resonance and timing for the two phases of the VCF envelope.

Foot control comes in the form of one footpedal and two footswitches. The footpedal (or "swell-shoe", as Wersi put it) can be assigned to control any of volume, VCF frequency and VCF resonance. Both footpedals can be set to control rotor effect on/off (assuming the effect has been set for the selected sound), sustain on/off and "Hawaii". The last transposes all currently-playing voices down a semitone when the footswitch is depressed, and then automatically glides back up to the initial pitch (or immediately returns if the footswitch is released). It's meant, as you may have guessed, to be an imitation of a Hawaiian guitar.

Finally, you can use the two footswitches as increment/decrement controls for transposing the whole keyboard in semitone steps, and/or for stepping through the Presets.

The MK1 includes a sophisticated implementation of MIDI Mono Mode, similar to those found on instruments like the Casio CZ1 and Ensoniq ESQ1. Thus each of the Wersi's eight internal manuals can be played polyphonically from a different MIDI channel, and can respond independently to MIDI patch change commands.

In fact, the Wersi allows you to assign a manual (or no manual) to each of the 16 available MIDI channels - meaning that each manual and the sound assigned to it can be played from more than one MIDI channel. Voice assignments appear to be dynamic, and the 20-voice version which we had for review managed to sound virtually limitless, even when using four-component sounds. At times, it was hard to believe such a wealth of sound could be coming from one instrument.

The MIDI basic channel (on which pitch-bend, controller and aftertouch data are received) can be set to any one of the 16 channels, and in turn assigned to any one of the internal manuals. MIDI transmission and/or reception of pitch-bend, controller codes, patch changes, aftertouch and note data can be selectively disabled.

Overflow mode (familiar now from instruments such as the Prophet 2000 and Ensoniq ESQ1) allows only notes which can't be handled by the MK1's onboard voice capacity to be transmitted over MIDI - allowing a second MK1 to be hooked up for a simply huge (ie. many-voice) system.


THERE'S NO DOUBT the MK1 Is a powerful, flexible and full-sounding instrument. It's far from being a half-hearted attempt at grabbing a slice of the pro synth market, and employs some pretty sophisticated technology to achieve its ends. In fact, it's hard to find any one important area in which the MK1's designers have skimped.

If anything, Wersi may actually have built too much into their first synthesiser. Because although you can only admire the thoroughness of the MK1's design, it's also difficult to ignore the fact that all that power isn't exactly presented in the friendliest, most easily accessible way. No synth player - no matter how experienced - is going to view that front panel with anything other than mild bemusement, even though it's the gateway to a huge archive of new sounds. And experience teaches us that instruments which overwhelm their users don't get used to the full.

The working musician who's in a position to afford the MK1 may not have the time to uncover all its features, and that's something of a pity, when you consider how sophisticated the Wersi really is.

A promising first entry into the synth market, then, but a machine unlikely to achieve classic status until its facilities are presented in a more easily understandable way.

Prices MK1 eight-voice £1653, 12-voice £1850, 20-voice £2337, ROM cartridge £49, RAM cartridge £45.50; all including VAT

(Contact Details)

Also featuring gear in this article

Wersi MK1
(EMM Jul 86)

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Music Technology - Copyright: Music Maker Publications (UK), Future Publishing.


Music Technology - Nov 1986

Gear in this article:

Synthesizer > Wersi > MK1

Gear Tags:

Analog/Digital Hybrid Synth

Review by Simon Trask

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