A SINGLE PROGRAMMABLE keyboard that combined digital clarity and invention with analogue warmth would, as the Financial Times might say, clean up good and proper.

It ought to be everything the synth player of '85 dreams about. And since some people would argue that Korg have been snoozing gently at the pro end of the market — last year's offering was the versatile, but budget-based Poly-800 — what have they come up with now the eiderdown's been pulled back?

The DW-6000 is a 'digital waveform' synthesiser... it's not akin to Yamaha's FM method of sound construction, but is, perhaps, closer to Casio's Phase Distortion technique exhibited on the CZ-101, though via a different route. Instead of the usual analogue square and ramp waves, the DW-6000 offers eight pre-set digitally profiled waveforms which can then be treated with analogue filters. That combination is not theoretically new, but perhaps the efficiency with which Korg operate, it is.

The construction, set-up and cosmetics of the 6000 show clear influences from the Poly 61 and Poly 800. Programming is via the now omnipresent parameter control. There are 64 memories: programme number, parameter number and value are displayed in separate LED readouts in the centre of the metallic grey panel and the synth will give you six-note polyphony across a five-octave C-to-C keyboard.

Though the desire for digitality is well crucial and modern, the 6000 shows itself as a slightly old-fashioned beast in a few ways. There's no touch sensitivity nor second touch control on the keyboard which, by the end of '85, will almost certainly make the Korg the exception rather than the rule. All the switches are white, positive-actioned buttons instead of the membrane bubble-switches that inhabit most new polyphonics. That's no bad thing. There are plenty of players around who prefer the firmer feel of an old switch. Those who still hanker after individual knobs and sliders instead of one-by-one parameter settings, are probably contemplating suicide.

Lastly, and not so essential, Korg have not followed their main rivals, Roland and Yamaha, in supplying RAM packs for extra memory. It's tape dump only. They have adopted the Yamaha example of a MIDI through socket to accompany the in and out, but facilities here are slimmer than the extensive options of, say, the Roland JX8P we reviewed last month — just channel selection, Omni mode either on or off (sending on all channels at once), and a third MIDI parameter to let you send just note data or all data. (It's here that the JX8P went into finer detail, dividing into bend on/off, patch change on/off, satellite keyboard only, and so on. No, I'm not going through the whole lot now, dig out last month's issue.)

As this is a pro-aimed keyboard, you won't find an arpeggiator or on-board sequencer — that, admittedly, is my inference and probably a snobby one. There's nothing 'amateur' about either of those functions.

The 6000 has two oscillator banks, two envelope generators (which, as it turns out, have almost as much to do with the digitality of the sound as do the oscillators, but more in a bit), a voltage-controlled filter, noise source, chorus unit, and what I took to be a fairly limited modulation section. Whatever happened to a choice of waveforms, or sample and hold? Though parameter control has made possible the reduction in the price of programmable polyphonics, the need to keep the number of parameters within limits has often meant that those above are the first features to go. The 6000 gives you one triangular wave LFO, plus controls for its frequency, delay and depth on the oscillators and filter.

The list of parameters, and their code numbers, is inscribed in glowing orange, green and lilac on the front panel to the right of the displays. The LFO experience prompted me to search for other missing items — NOT corner cutting exercises, but facilities that no longer apply because of the move to digital waveforming. We say goodbye to pulse width modulation (no square waves, y'see) and oscillator syncing.

Parameter values can be stepped up or down by two buttons, or shifted more dramatically via a slider. In the majority of cases each parameter is broken into 32 steps (0-31), the exceptions being filter cutoff (64), detune (7), interval (locked off at thirds, minor thirds, fourths and fifths), and those sections such as the mildly hissy chorus which are simply on or off.

To the left of the displays is another pad of 'notes', this time listing the 64 factory-loaded sounds and descriptions — a helpful guide in the short term but, since all of them can be written over with your own patches, I wonder how handy 'Organ With Percuss' is going to be when it's really 'Dog Under Car'? 'Break Dance' and 'B-Jean' are going to date you as well, but since it's claimed that 80 per cent of synths go through life without having a single pre-set changed by the owners, I'm doubtless being a quibbling old get.

One more point, I've always admired Korg's 'Bank Hold' idea where you select the bank, punch hold, then only have to select the second number each time in order to change the memory position within that bank. The parameters have also been divided in this way (VCF is bank '3' — 31 for cutoff, 32 for resonance, etc) and certainly speeds what can be a tedious method of programming.

But you all want to know about the digital bit, don't you? At the extreme right of the panel is a list of eight waveforms showing their shape and spectrum analyses. Neat bar graphs detail the harmonic strengths though there is no room to number the harmonics. These are pre-set waveforms so all you can do is choose one shape for each oscillator, but each does have a very distinctive character.

They are not samples but (apparently) harmonic mimics of real instruments whose waveshapes have been analysed and imitated, and the resulting forms encoded in a pair of 256kbit Read-Only-Memory chips. Devices that have received the Mike Yarwood treatment include brass and strings, violin, acoustic piano, electric piano, synth-bass, saxophone, clavinet and bell/gongs. Of course, it's still up to you and the rest of the synth to produce the envelope and filter patches that make sense of these additive harmonic offerings.

After half an hour of flicking through the factory sounds, you begin to understand how the waveforms behave. For example, '8' has 12 widely-spaced harmonics falling after the initial burst of first and second harmonics common to all the shapes. These drop at even intervals like 6, 10, 14, 18, 22 and so on, and the waveform is a dead ringer (ho, ho) for your bell noises... clangy, metallic, with all the swirling steeliness you'd expect from a grandfather clock. You'll find it behind 'Bells 1', 'Vibes', 'Celeste' and several others.

But waveform '4' has two well-defined peaks in its spectrum. The first and second harmonics are powerful, then three to eight fall off sharply, nothing for 9 to 13 then sudden spikes at 14 and 16. Again there's a bell-iness brought about by the even harmonics but now subdued... a bonus tone rather than the whole sound. Waveform '4' is at the heart of the electronic piano/Fender Rhodes impersonations where that extra metallic 'chip' is needed.

And so the process goes on. Waveforms '1' and '7' are both reedier and closer to analogue oscillator shapes; '2' is softer without the extra metal overtone; '3' does have overtones, but not so clearly defined; '5' follows '3' but more nasalish and, '6' is perhaps the evenest waveform with the smoothest spread of harmonics. ('1' is often used for strings, '3' for acoustic pianos.) The art is in blending them so, for example, a piano has waveform '3' on oscillator bank one to provide the brightness and body, with a roughly half-level oscillator two set at waveform '8', 16ft, to give that tangy wireness particularly prominent at the lower end of the piano where the strings are thickest.

Perhaps the best example of what the DW-6000 can do (that ordinary analogue synth oscillators can't) is the 'Break Dance' patch. One oscillator bank has a thick 'synthy' waveform, the other goes for number '8' — together they give you a solid, piano-like sustain, plus tubular bells on top — a sound with a strong 'layered' feel and closer to some of the DX7's orchestral mixings than I've heard from many other synths.

The surprise is that the Korg does still succeed in producing warm string sounds, fat analogue brassy patches and thumping bass lines. The ability to lock all 12 oscillators in unison does things to the digitality that you won't hear elsewhere. One note full of bells takes on an oily, wobbling, semi-phasing effect that directs shivers of Hammer House terror up your vest.

But though this may be digital-based sound creation it is NOT FM. Yamaha's system is based on the interaction of the sine wave operators — as each moment passes the waveform feeds back on itself, so changing constantly. The Korg approach is one of commencement and treatment. It has the attack of FM, but not its texture.

No matter — it also has something of its own.

If one of the appeals of FM synthesis is the activity in the sound then a method of aspiring to this would be to add sections to analogue ADSR envelope generators, and that's what we have in the two parameters called Break Point and Slope.

They fall between Decay and Sustain. Imagine that Break Point has taken the place of Sustain in the old ADSR set-up. After your initial decay the filter (VCF-EG) or volume (VCA-EG) falls to that level (between 0-31). If the Break Point is zero on the VCA envelope generator, then the volume will drop to nothing.

The Slope value can then determine how quickly the volume rises to the true Sustain level. If Sustain is maximum (31) and the Slope is zero, it will leap in a split second back to full whack. If it's 31, it will gradually climb out of the silence set by the Break Point. Or you could have the Break Point at 31 and the Sustain at zero and listen to it fall away.

This extra peak is what helps the DM-6000 sounds 'grow' in the middle of their lives. Sounds that begin as hard percussive clicks can blossom into sustain half a second later. When Break Point and Slope values are applied to the filter, it's the tone of the waveforms that vary in mid-sentence.

It's this expansion of harmonics half way through that lets the DM-6000 do the rasping church organs, and heavily-bowed cellos that are the province of digitalish keyboards. Even monophonic lead lines (especially bass) can benefit as the Break Point and Slope let you decide how much 'after-sound' hangs on in the low frequencies once you've twanged the imaginary bass string, and whether that 'after-sound' should be soft, sharp, plucked or sustainy. It's an effective extension of the ADSR envelope generator and one that might have benefited normal analogue oscillators little, but acts as an inspirational foil to the Korg's digital bunch.

But does the DW-6000 work? In its combination of tones, certainly. An analogue synth couldn't produce the digital voices of the Korg; a straight FM synth couldn't mimic its analogue behaviour (though the chorus unit is a BIG help).

When I unpacked the DW and plugged it in (a strange, two-pin mains plug — disaster if you lose it) I was first fascinated, initially lost interest, then on continued playing grew to like it again (an ADBSSR reviewer, maybe). But all the time, my major hesitation remained one of price.

The keyboard manufacturers may well place snipers on One Two's rooftops but, truth is, with hard bargaining, you can get a DX7 for a figure not far off the DW-6000's list.

But, if you can only afford one synth, are pressured (by the bloody vocalist) into getting some of those digi-sound-things but KNOW you're not going to be able to do without your analogue thunderstorm-and-Stradivarius overkill, look it up.

KORG DW-6000 digital waveform synth: £1099

CONTACT: Rose-Morris, (Contact Details).