With the introduction of digital FM synthesis and the DX range Yamaha did achieve some kind of genuine breakthrough in affordable high quality sound synthesis.

Not that the concept of FM was completely new, but by presenting it as a complete and uniquely powerful means of music synthesis, in a workable and unusually affordable package, Yamaha undoubtedly deserve a lot of credit.

LIFE BEYOND PRESETS

One of the drawbacks with FM, and indeed possibly part of its initial attraction, is the seemingly ineluctable quota of jargon that goes along with it: operators, modulators, carriers etc. Though uniquely powerful, it is also uniquely difficult to get to grips with in terms of programming, and the majority of DX owners are still at least partially in the dark once they step beyond the presets.

This one possible drawback has been the focus of the competition since FM made it big, and the threat of producing an FM-like system without the confusion has long been in the air. What with the much publicised digital revolution and the success of Digital FM, every synth manufacturer in the world has been plastering the term digital all over every product so that it is now fast becoming the technoplatitude of the decade. Since FM, however, low-cost synthesis revolutions have been a little thin on the ground.

LEGENDARY

So now we have what has to be seen as Casio's answer to the FM legend: The CZ series of which CZ-5000 is king over the lesser CZ-1000 and the junior CZ-101. These instruments are based on what Casio are calling 'Phase Distortion' (PD). Obviously there can be no official acceptance of the similarities between the two systems, but the similarities do exist.

If you are familiar with the 1000 and the 101, the CZ-5000 will hold few mysteries for you. It's basically a 1000 with 16-note polyphony and a number of extra facilities including a built-in 8-track, 3,400 note sequencer and keyboard split BUT no touch sensitivity. At a RRP of £955 (and it will almost certainly sell for less in the shops) this possibly shouldn't come as any surprise, as it is exactly the same price as the DX-9 which can lay claim to neither integral sequencer nor keyboard split, let alone touch sensitivity. The 1000 and the 101 offer such incredible value for money, it would be easy to get churlish and expect the world from the 5000 — in fact it'd doing pretty well as it stands.

On first appraisal, the CZ-5000 (or any CZ for that matter) looks deceptively simple. The voice generating system can be thought of as comprising a pair of DCO's, a pair of DCW's and a pair of DCA's. The DCO and DCA parts are quite simple: just like VCO's and VCA's, but digitally controlled; then by taking the DCW bit as being just like a digital VCF, all possible sources of confusion are at once removed. In their eagerness to demonstrate the CZ's simple programmability (as compared to the more esoteric DX range) early Casio demonstrations rather encouraged this simplistic concept of phase distortion. But there are very definite differences in programming techniques between a normal analogue synth and a CZ; fluency on the former, whilst being of great assistance, won't ensure immediate competence on the latter.

In the simplest of DX algorithms, for example, the frequency of a sine wave, termed the Carrier is controlled by a second sine wave, the Modulator, so that as the instantaneous amplitude of the modulator sine wave slews up and down (maybe several thousand times a second), so too does the frequency of the carrier. This creates a set of frequency side bands and harmonics resulting in a new, richer sound, the tone of which depends upon the relative frequencies and amplitudes of the two sine waves. One point here is that the shape of the wave form is being Altered, as opposed to the standard analogue VCF process of simply filtering out part of an original wave form. Due to the very limited number of variables involved, drawing a mental map of how a standard VCF effects the timbre of a sound is fairly easy. With the number of different permutations provided with FM, the process becomes a little more difficult to track.

The apparent complexity of the Yamaha system is part and parcel of the creative freedom that it affords the programmer. There is a very high degree of control within it, but it can seem rather like being given a pile of bricks as a DIY building kit.

PREFAB

The Casio 'Phase Distortion' voice generating process, in contrast, is somewhat more prefabricated. It starts with the selection of one of 8 possible wave shapes that are recorded into digital memory (ROM) at the factory, and this can be seen as the DCO section. As this wave form is read out from memory, the programme can alter or 'distort' its phase angle — which effectively alters its shape, its harmonic content and, naturally enough, its sound. As with the FM system, this is far more than filtration, it's a method of positively changing the form of a sound wave. However, by starting with an already complex wave form, as opposed to a sine wave, Casio have made the 'building blocks' with which the user has to work larger, and hence simpler to utilise.

There are two 'channels' for sound creation and for each channel the DCO section offers you a selection of 5 basic waveforms and 3 resonant waveforms (8 in all): 1. Saw-Tooth 2. Square 3. Pulse 4. Double Sine 5. Saw Pulse 6. Resonance 1 (Saw-Tooth) 7. Resonance 2 (Triangle) 8. Resonance 3 (Trapezoid)

You can combine any two of the first five waveforms, or any one of them with any one of the resonances, in order to create the basic wave form of your sound. The resonances act partly like the resonance control on a VCF in that they determine the way a note 'sings'.

For all three stages in the chain, ie the DCO, DCA and DCW Casio offer a separate envelope generator that provides 8 levels and 8 rates with which to contour an effect (these are similar in concept to the Yamaha EG's). An excellent idea is the addition of an 'end point' that you can insert anywhere in the envelope so that you don't have to go through laboriously programming all 8 steps if you don't need them. Similarly, the sustain point can also inserted anywhere, making the EG shape extremely flexible, and hence more powerful.

A description of how the DCW affects the sound is far from easy, but there does seem to be a more or less easily understood set of rules to learn as you go along, although owing to limited access. I can't speak from any great experience.

The Yamaha system manages its rich timbres from complex combinations of 4, 6 or 12 (DX-9, 7 or 1 respectively) sine wave generators. This means that when programming new sounds, the programmer has to bear in mind a large number of interactive variables — it's a tricky old business, and whilst the instrument is a huge success, many users are frustrated by their own inability to come to grips with it. The CZ-101 cuts a lot of the work out by presenting you with some ready made waveforms, and a more easily understood method of changing them.

Increasing the size of the building blocks must mean a diminishing of the detail with which you can programme, but it should also make the process much more accessible to the average musician — amateur or professional.

PRESETS

The CZ-5000 comes with 32 internal permanent presets plus a plug-in RAM facility for a further 32 of your own sounds. With such different cultural backgrounds it is understandable that what the oriental ear looks for in a sound might differ from the requirements of a western rock musician. The 32 factory presets aren't too strong as compared to the currently accepted norm, although Richard Young, Casio's UK professional products demonstrator, has already created a range of impressive voicings that demonstrate very clearly the instrument's full potential. (Hear the tape)

It is unlikely that anyone would present the DX range as a replacement for more conventional synths. They've entered the market with a very unique and easily identifiable set of excellent sounds, and are very much an addition to, rather than a replacement for, analogue-type synths. The CZ range also has a fairly unique range of sounds, although it definitely tends more towards the fatness and warmth of analogue, and less towards the ultra-bright clarity of the Yamaha's percussive sounds. For instance, there are no convincing electric piano or bell sounds available on the CZ yet they are a couple of the DX mainstays. The Casio, on the other hand, offers some excellent, big thick 'synthy' sounds which seem like a kind of digital/analogue hybrid. The CZ-5000 with its extra quota of voices (16-note polyphonic as opposed to 8-note capacity of the other CZ models) is especially impressive in this respect.

Whether it will, with experience, be possible to reproduce DX sounds on the CZ, is impossible for me to answer — the variables are of a different form, and it would take a computer to work out exactly how the two systems relate to each other.

SEQUENCER

The sequencer has full edit facilities and is very easy to use, although in the real-time mode, the lack of any auto-correction puts a lot of pressure on the player's timing, and actually precludes any really complex sequences for anyone but the hottest players. Another apparent limitation is that of not being able to loop a sequence, in order to play it repeatedly. Surely these are both simple software anomalies to be cleared up at a later date (?). Due to lack of an owner's manual, little was known in the UK at the time of the review regarding step-time programming.

Although the 5000 claims a programmable split, it can actually only store a single split set-up in a dedicated memory. A split cannot be part of a normal preset.

As with the other CZ models, the MIDI implementation is very comprehensive, and allows not only Omni and Poly modes but also Mono mode. The latter allows the 5000 to be used in the Polyphonic mode, as up to 16 separate instruments, ie a separate melody can be sent to each of the four voices; useful if you're using a mono-mode MIDI sequencer, or a personal computer as a controller.

We must now wait to see if Casio come up with a touch-sensitive CZ. That would be very interesting.