Additive synthesis finds another outlet in the K3, a polyphonic synth whose friendliness is aided by Hybrid Arts' visual editing software. But do the sounds come up to scratch?

IF THERE'S ONE THING more pleasantly surprising than the number of budget sampling keyboards to appear over the last couple of years, it has to be the variety and popularity of synths employing digital oscillators and analogue signal processing. Especially pleasing are the very different approaches taken towards implementing this hybrid: PPG's wavetables, Sequential's Vector Synthesis, and so on.

Over the past year or so, some simpler, less expensive methods have emerged which may have done little to transcend the limitations of static digital waveforms, but have at least put the "digital sound' into the realm of budget synths. In some ways, this is also true of Kawai's K3 digital wave memory synthesiser, but Kawai have taken steps to ensure that the K3 is not merely another six-voice, five-octave, velocity- and pressure-sensitive MIDI keyboard synth.

For a start, they've included 32 preset digital waveforms covering a wide range of "real" and synthetic timbres, but to take it one step further, the K3 allows the user to create custom waveforms using additive synthesis techniques (either on the K3 itself, or using Hybrid Arts' K3 Wave Edit Program for the Atari 13OXE computer).

Voice Description

VOICE STRUCTURE IS based on the two-oscillator, mixer, VCF, VCA formula made popular by such synths as the Prophet 5 and Oberheim OBx, though as mentioned above, the analogue oscillators have been replaced by far more stable digital oscillators, which are also capable of producing a greater variety of waveshapes. So from the word go, the K3 produces basic timbres beyond the scope of most analogue machines.

Having two independent digital oscillators which can each take on any of 33 digital waveshapes gives the K3 the added advantage of being able to blend two very distinct timbres, which may also be detuned by coarse or fine amounts for an even wider timbral palette.

A nice touch in the pitch department is the K3's autobend feature, which bends into the note played by a programmable amount (positive or negative). Thus the K3's brass patches can achieve an "overblow" effect. All six voices can be played in unison when the Mono parameter is switched on, and Polyphonic glide can also be achieved, using the Portamento and Porta Speed parameters.

The LFO is the primary modulation source, and can be routed to the oscillators (both at once only), to the VCA, and to the VCF. It can be programmed for the standard triangle, sawtooth and square waveforms, but also has random and "chromatic random" waveforms for a variety of sample/hold-type effects. The inclusion of an LFO delay was a good move, since this turns out to be the main way to increase the amount of LFO modulation gradually.

A Balance control sets the basic timbre prior to dynamic filtering in the VCF section. Because of the timbral contrasts possible between the K3's oscillators, the Balance control setting can have as drastic an effect on the overall sound of the program as the filter cutoff frequency; yet because of the complex harmonic structures of digital sounds, the effect is much harder to describe. One of the K3's strong points is that keyboard pressure can affect this balance. On some programs (internal patch 35 in particular), bearing down on the keyboard causes all voices to change tone with an effect not unlike the Sequential VS' mixer envelope modulation, though the K3 does not do so polyphonically. It would have been nice if the K3 did allow LFO modulation of the balance, but as it is, the pressure modulation gets full points in this area.

The four-pole VCF section features pretty standard controls - cutoff, resonance, envelope amount, and the standard ADSR envelope parameters - but an additional low-cut filter helps tailor the sound just a bit more. No frequency control exists here, only a cut amount. Few of the factory programs actually use this parameter, but it does help remove a bit of "boom" from some programs when played in the lower octaves.

The filter section is also subject to velocity and pressure modulation, affecting the cutoff naturally, and there are no surprises here, though I was a bit disappointed to find that velocity adds to the filter cutoff frequency, rather than scaling the cutoff after the addition of the envelope; I find the latter method more effective in most cases. For the most part, though, the filter helps bring out the analogue character of the K3 quite well.

The final stage of a K3 voice consists of the VCA with its ADSR, and the stereo chorus. Velocity-sensitivity of the final VCA, like the VCF, can be controlled by key velocity per voice, or by pressure for all voices.

The stereo chorus has seven preset settings which work adequately, though the lack of programmability in this area is a bit of a let-down. Still, the stereo effect is always an effective way to add depth to just about any sound, and this is precisely what the K3's chorus does.

The five-octave keyboard has a good, stiff action, but I found that the note turn-off threshold was a bit low for my technique, and while this does allow for faster-than-average retriggering, it takes a bit of getting used to.

Sounds

SO, KNOWING WHAT to expect from the K3, the next questions are: 'how does it sound?" and "what's it like to program?"

The factory-supplied programs are as good a starting place as any. The K3 holds 50 patches internally, and can access an additional 50 on cartridge. Kawai are kind enough to supply a RAM cartridge with their production units, so owners can get on with programming from the moment they remove the K3 from its box.

Kawai have recorded the 50 internal factory patches in the K3's ROM as well as in RAM. To reload all 50 patches, simply hold down the first three keys on the 61-note keyboard while switching power on. This also ensures that no matter what horrible fate might befall the lithium battery within, the K3 can still produce useful sounds without the user resorting to an unscheduled programming session.

Patch selection on the K3 is of the single key-press type, and upon selecting a patch, the left-hand two display digits show the new patch selection, while the remaining four digits remain blank. The patch selector buttons double as parameter select switches, and for organisational purposes are ordered in columns rather than in rows.

The factory programs contain most of the analogue standards like strings, brass, electronic piano, and organ, along with some meaty solo synth sounds and admirable digital bell tones. But I wish more of the patches demonstrated the pressure/balance facility more often, as this is one aspect of the K3 which really makes the unit shine. Still, many of the patches make good use of the autobend and mono (unison) features, showing the K3 to be capable of some rich, warm textures as well as some strong lead sounds.

Pressing the Parameter Edit switch puts the K3 into edit mode, and the remaining display digits come to life, showing the last parameter selected and the current value. Parameter values are adjusted by a large "Increment" dial to the left of the switches.

Only patch parameters can be adjusted at this stage. There is yet another set of parameters which affect the K3 as a whole, and deal with its MIDI mode, channel, and other functions. This second set of parameters (known as "Masters") is selected for editing by pressing the Master Edit switch, which is logical enough. Just like the parameter select switches, the master switches use the patch select buttons in master edit mode. The K3 labels the masters in black lettering and the parameters in white, so there is an obvious distinction.

Although random access to parameters may not be anything new, a pleasant side-effect of this method is that each time a patch is selected, the last parameter edited (prior to that patch being written into memory) is automatically called up, though the display doesn't show this until the Increment dial is adjusted. This means you can have specific parameters ready to edit with the dial for certain patches.

For example, on one patch the dial could control the depth of LFO modulation, while on another it could change the wave used by either oscillator.

As it turns out, this is a good thing because, much to my disappointment, the K3 has only one wheel, and it is dedicated to spring-loaded pitch-bending. Thus the K3 relies entirely on the dial to add further performance control, and though the flexibility of the dial's programmable function is very useful, the dial is placed too far away from the pitch wheel to act as a true replacement for the modulation wheels so many musicians have known and loved.

Over MIDI, however, the K3 accepts mod wheel change messages, and automatically assigns them to control the depth of LFO-oscillator modulation. Although this is consistent with other synths, it's a shame that the advantages of the Increment dial control are lost over MIDI (at least when using a standard mod wheel).

The K3's switches are of the "under mylar" type (first popularised by the DX7), and part of the front panel is recessed to accommodate the mylar strip which bears the switch labels. This provides a convenient area into which the factory-supplied patch and waveform reference card fits neatly. To the far left of the control panel is the master volume switch, which works in conjunction with the rear panel Level switch to set the final volume range of the K3.

While we're looking at the back panel, we also find the two audio outputs (right and left, the latter doubling as a mono output when the right output is not in use), a memory protect switch, standard MIDI In, Out, and Thru jacks, and Release and Program Up footswitch inputs. Both footswitch inputs operate with a normally-closed momentary footswitch, so you have to be sure you have the right kind plugged in, or all the programs drone. It's interesting how Kawai have implemented the release footswitch function; depressing this switch essentially holds any notes played, so that the VCA and VCF envelopes remain in their sustain phase. This method is different from that used by many synths, which have two programmed release settings.

The Program Up footswitch normally just steps through the patches, but when the Link function is selected, the footswitch steps through a programmed series of patch changes. A nice touch for live performance. Finally, the Link switch doubles as the Master Tune function selector when in master edit mode.

User Waves

THE K3 COMES supplied with 32 waveforms, ranging from woodwinds and brass to vox humana and pipe organ. Though these blend together well, you are still limited to 32 timbres (though that's not really much of a limitation compared to the sine, triangle and square waves available on analogue synths), and half of the trick to programming the K3 is finding the right combination of waveforms to start with.

The K3 reserves wave 32 for a user-definable waveform, which is designed with an additive synthesis facility to offer 128 harmonics of variable intensity. A second user waveform resides on cartridge (also in location 32), but unfortunately, there's no way you can combine the two into the same patch.

User waveforms are built up using two main parameters: Harmonic and Intensity. Creating waveforms is a bit more involved than merely adjusting these two parameters, though.

First, you need to select a patch which uses waveform 32, and then edit that patch so that the user waveform is isolated. Entering master edit mode lets you select the Harmonic/Intensity function, which displays the currently selected harmonic and the corresponding intensity. Pressing Harmonic/Intensity toggles between the two parameters, but no change can be heard in the waveform until you press the Write switch. The user waveform is then updated and can be heard.

Unfortunately, in order to return to editing the waveform, the Write switch must be switched off again. Though this is only a minor detail, if you plan on spending a lot of time editing the waveform, this second keypress can become a nuisance.

Kawai have incorporated a couple of helpful harmonic sculpting tools via a Copy function. This lets you design a contour - say a two-step drop per consecutive harmonic and then, by adjusting the harmonic number with the Increment dial, apply these decreasing intensity values to all harmonics you step through.

An alternative method to using the K3's built-in waveform editing functions is Hybrid Arts' K3 Wave Table Editor program, written for the Atari 13OXE computer and MIDI-Mate interface (available to special order in the UK from Syndromic Music). The program, which is considerably more colourful than other Hybrid Arts programs, makes waveform creation much easier by displaying all 128 harmonics simultaneously. The left and right cursor switches select the desired harmonic, while the up and down cursor switches adjust the harmonic intensity.

Again, in order to edit the user waveform, you must first select a patch which has waveform 32 isolated (ie. the Balance control set entirely to that oscillator). Then each time you wish to hear the edited waveform, you must type on the Atari, then reselect the patch on the K3.

Since the waveform edits cannot take place in real-time (presumably due to lack of K3 processor power), a lot of switch-pressing is required to make new waveforms. Still, there are 128 harmonics to work with, though I had a hard time hearing any significant changes in tone when harmonics above number 60 were adjusted.

The program also features patch-programming facilities with envelope displays and so forth, but most important, there is a patch librarian.

All MIDI functions are set from the master edit mode, including the MIDI mode (Omni or Poly), the receive channel, and the transmit channel. All MIDI enable and disable controls depend on the Function parameter, which has five values, each one corresponding to a different combination of enabled MIDI messages.

Kawai's rack-mounting version of the K3, the K3m, differs from the K3 in that it sends and receives on the same MIDI channel, and a Note Priority parameter replaces the Send Channel parameter (43). And the K3m has an advantage over the K3 in that, having no keyboard or wheels, the missing mod wheel is not a problem.

Verdict

THERE IS STILL a need for synthesisers which offer a wide range of sounds without having to resort to complicated programming techniques. And although the user wave feature could have been much more effective had the K3 the capacity for more of them, it does give the programmer just that extra amount of control over new patches.

Both the K3 and K3m have a number of features which set them apart from the competition, and if they may be taken as an indication of where Kawai plan to go with future synthesisers, there's plenty more to look forward to as well.

Prices Kawai K3 £1085; Kawai K3m £785, including VAT

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