Kawai's new K4 comes to us with a new method of synthesis: - Digital Multi Spectrum - but how much is new and how much is more recycled technology?

GIVE IT A cursory once-over and you could be forgiven for thinking that Kawai's new K4 is actually their old K1 in disguise. A superficial glance at the controls reveals familiar pitchbend and modulation wheels (what, no joystick?), two-line LCD, Multi and Single buttons, four bank select buttons and two rows of patch select buttons. Kawai have obviously decided not to give their followers any future shock.

In many other ways, too, the K4 reveals its heritage, and anyone familiar with the K1 may be forgiven for sharing a sense of deja vu as they read this. But there are differences, so read on and all will be revealed.

The K4 has a five-octave velocity- and pressure-sensitive keyboard with the pitchbend and modulation wheels situated to the left, rather more convenient than their placement above the keys as on the K1. The buttons are plastic as opposed to the K1's squidgy rubber ones and the keyboard has a sprung synth action which should be responsive enough to satisfy piano players who don't violently object to playing synth keyboards.

The sound sources are produced by a DMS (Digital Multi Spectrum) tone generator (more about this in a moment) which is presumably an updated form of Kawai's VM (Variable Memory) synthesis used in the K1. It is capable of handling up to 16-note polyphony.

A single sound or Tone is referred to as a Single patch and a combination of Tones is referred to as a Multi patch. There are 64 of each type of patch stored in four banks of 16. A RAM card can be used to store an additional 64 patches of each type.

The first thing you do with a new instrument is check out its presets. I can't tell you what the default sound is like - the one that usually makes you want to buy the thing - because someone decided to replace it with a duplicate of the sound in position two. A quick run through the other sounds, however, quickly reveals the K4's forte: pads, combination and layered sounds - yes, even some of the Single sounds move and swirl and contain several different types of Tone within them.

Multi sounds allow you to combine up to eight Single Tones into one gigantic arrangement. The potential complexity of such a combination has to be heard to be believed, especially as one of the major additions to the K4 (over the K1) is a digital filter. Now we're getting down to business.

SOURCE SECRETS

DMS IS A 16-bit system and the sounds it produces are squeaky clean. The perfectionist may detect an ever-so-small amount of background residue when some of the effects are used but I'd have no hesitation in using the K4 for recording and I've no doubt it will have already appeared on many a record even as you read this.

As the sounds do bear a passing resemblance to those produced by Roland's LA and Korg's Al synthesis, let's look at the K4's Tone structure. (If you've managed to master Roland's LA synthesis in its myriad forms, this will be a piece of fish.)

A Single patch can be built up from four Tone Sources which can be in a Normal, Twin or Double arrangement. Normal allows two Sources to be fed to a single filter, Twin allows two pairs of Sources each to be fed to separate filters and Double routes the Sources through the filters in series. It's worth noting, though, that Twin and Double modes reduce the polyphony to eight notes.

A Source can comprise of one of 96 DC (Digital Cyclic) waveforms composed of up to 128 harmonics, or one of 160 PCM waveforms. The DC waves include traditional analogue-type waves (sine, square, rectangle and so on) plus a variety of instrument sounds such as organ, bass and piano. Some you may use alone but many will find a home alongside other waves to help add character.

The PCM waveforms are sampled sounds and include pianos, strings, voices, guitars and basses along with many other instrumental sounds and 23 Reverse and Loop effects.

Four Source buttons on the front panel are used to select the Sources during sound construction and editing, and four more are used to mute them. The LCD helpfully tells you if the wave is DC or PCM but you have to look up the name in a separate Wave list manual. Shame, as there's room in the LCD for the name, too. It seems Kawai haven't learned from criticisms of the K1, as the lack of wave names was its biggest fault (some would say only fault) except, perhaps, for the lack of a filter.

The DCO button is used to set the waveform values, fine and coarse tuning, pressure, vibrato, autobend and key tracking (whether the keys are to play normally or play a fixed pitch).

The editing functions are accessed from buttons on the front panel. Parameters are altered with a Value slider (shades of the DX7's data entry slider) and +/- buttons. A Recall button lets you compare the original patch with the edited version and you can copy Sources and filter settings from one patch to another.

The Common Group edit functions act on all the Sources in a patch. They include ring modulation and a variety of keyboard modes which determine what happens if a key is pressed before the other is released. You can assign individual pitchbend, pressure, modulation and velocity parameters to each patch, plus autobend, which is useful for voice effects and ethnic instruments.

The Source Common functions allow you to introduce a delay time for each Source from the time the key is pressed to the start of the attack phase (arguably this may be have been better placed in the DCA section). It allows you to construct sounds which build up in complexity by introducing Sources over time and to create echo effects.

Here, too, you can select one of eight velocity curves ranging from a direct linear response curve to ones which only produce sounds if the keys are struck hard or soft (more scope for the layering of sounds). There are also eight keyboard scaling curves which change tone and volume depending on the position on the keyboard of the key which is played. Use these to set up crossfade effects.

The manual includes helpful diagrams which show exactly how the volume relates to velocity and key position (but make sure you read the correction sheets for the full picture).

The DCA section has traditional ADSR (Attack, Decay, Sustain and Release) phases plus an overall level (volume) control. Some die-hard synthesists may prefer a multi-stage envelope but this will do me just fine. The number of waveforms and editing options more than compensate, and don't you think life is complicated enough?

The DCA Modulation functions determine how the level is affected by the keyboard. Options include setting velocity, pressure and keyboard scaling depth, and time modulation velocity, time modulation release velocity and time modulation keyboard scaling. The time modulation parameters let you alter the envelope attack, decay and release times according to how hard the keys are struck and their position on the keyboard. This may be merely useful when used with a Single patch but its potential is far greater when that patch is used within a Multi patch.

Vibrato can be produced by adding LFO to the DCO, and wah and filter sweep effects are possible by adding it to the DCF. There are triangle, sawtooth, square and random waveforms and the LFO can be made responsive to pressure. The vibrato for each Source can be turned off and a delay can be added.

THE FILTER

AND SO TO the filter section. This is probably the biggest difference between the K4 and the K1 and, arguably, its greatest contribution to digital synthesis. You can filter any of the waveforms, not just the DC ones, and two filters can be assigned to a Single patch as previously mentioned.

DCF parameters include cutoff and resonance frequencies (specified numerically rather than in

Hertz, but no less useful for that) which operate in a similar manner to analogue controls. This is nice. There are also velocity, pressure and keyboard scaling depth controls and the LFO can be toggled on and off.

The DCF Modulation parameters are similar to the DCO Modulation parameters and are used to alter the filter from the envelope and keyboard.

THE EFFECTS

THE K4 CAN store 32 effects internally (number 32 is normally used as a bypass) with 32 more on a RAM card and you can route a patch through one of these. In comparison, the K1 II (reviewed MT, October '89) effects begin to look like the afterthought they undoubtedly are. There are 16 different types of effect including reverb, delay, overdrive, chorus, flanging, feedback and various combinations of these.

Each effect has three parameters which vary according to the type of effect it is. For example, the reverb parameters are pre-delay, reverb time and tone (brilliance). The effects certainly enhance the sound which is why they are there in the first place.

A patch can also be assigned to a Submix Channel, A to H. These contain pan positions of the sound (-7 to +7) and effect levels. This allows you to create settings in the Submix section, and route the sounds to any of them by assigning them to a Submix Channel - rather like plugging the sound into an audio mixer channel. It's easier in practice than it may sound on paper.

"The K4's Source Common functions allow you to construct sounds which build up in complexity by introducing Sources over time and to create echo effects."

MULTI PATCHES

A MULTI PATCH is a combination of up to eight Single patches along with various parameters which tie the sound to key velocity, keyboard range, tuning, transposition and so on. The two rows of eight patch select buttons are used to select and mute the eight patches (or sections in K4 talk) which make up a Multi patch.

The Edit button lets you set the overall Volume of the patch, the effect to which it is routed and its name.

There are four basic editing functions: Instrument Group, Zone, Section Channel and Level. As on the K1, internal Multi patches can't use external Single sounds (the ones in a RAM card) and vice versa. Otherwise any of the 64 Single patches can be assigned to any of the sections.

Zone Is used to set the upper and lower note limits for the individual sections. If you set the low limit higher than the high limit (are you still with me?) the patch will only play at the upper and lower ends of the keyboard and not in the middle. There is also a velocity switch here which can make a section sound only if either you play the keys hard or soft - more scope for layering.

The Section Channel is used to set the MIDI receive channel of each section. Simply, it gives you easy access to eight multitimbral sounds. It also allows you to say whether the section can be played only from the keyboard, via MIDI or both.

Level sets the volume level, transpose and fine tuning parameters for the sections. It also routes the sections to a Submix Channel which works in the same way as for Single patches.

If you've been following this (and I'll be asking questions later) you should realise how the K4 excels at "moving" sounds - the delay before the envelope sets in, the layering of four Sources into a single patch, the subsequent combination of up to eight of them into a Multi patch and, of course, the inherent harmonic movement produced by the filter all lend themselves to superb layers and banks of sound. You could use the K4 to write a film soundtrack all by itself. (If someone gives me the commission I'll do it.)

The K4 is capable of more stationary sounds, too. The instrument PCM waveforms, for example, can produce convincing solo instrument sounds although the presets, naturally, concentrate on combination sounds. The pianos are convincing but don't top the ones in Yamaha's EMT10, for example. Other than that minor observation, there should be a great enough variety of strings, basses, choirs, guitars, brass sounds and so on to keep you happy until you start creating your own.

THE DRUMS

IN KEEPING WITH popular trends (as evidenced by Kawai's own K1 II), the K4 has a separate drum section, independent of the Single and Multi patches. It can be played from the keyboard by pressing the Drum button but, more usefully, it can be used to play drum tracks created on an external sequencer.

A set of 61 drum patches, one for each key from C1 to C6 can be programmed. The drum section uses two Sources for each key and settings for wave, decay, tune and level can be made for each Source. There are 42 specific drum-type sounds again, all PCM, but any of the waves in the waveform library can be used. The range of sounds is very good - especially liked the timbales - although there's no quijada.

It will be interesting to see what the programmers make of the K4. The potentially limiting internal architectural structure of a synthesiser based around a fixed number of sampled tones may have been side-stepped by the inclusion of a filter but, although its contribution towards shaping the sounds should not be underestimated, the number and variety of separate and distinct sounds remains to be determined.

SYSTEM FUNCTIONS

THERE ARE A host of options lumped together and accessed by the System button. These include tuning, transposition, local control and velocity switch point (to determine at which point the switch between playing loud and soft takes place).

System is also used to set transmit and receive channels and to determine what MIDI data is transmitted and received - program changes, pressure, bender, modulation, hold and velocity. The recognition of system exclusive data can be toggled on and off, too.

The top left-hand corner of the LCD shows when MIDI data is being received - a feature that's becoming more common and can be very useful. The sounds can be saved and loaded via MIDI data dumps either individually or en masse.

MIDI & MULTI MODES

SINGLE PATCHES ARE selected over MIDI using program change numbers from 0 to 63, Multi patches are selected with numbers 64 to 127. Patches in RAM cards must be selected from the front panel or by sending a system exclusive message. I kind of think a program change table would be useful here, but I won't quibble.

You can change the patch in a section in Multi mode by selecting Section in the Receive channel options and then simply sending the relevant patch change number on the section's MIDI channel. That's the way multitimbral setups should work, of course; but they don't on some instruments.

POWER & THE MANUAL

THE POWER SUPPLY is still external (like the K1 and although it reduces the possibility of mains interference finding its way into the audio signal, it does make it easier for a power lead to be pulled out or snapped off during a gig.

The Link Play function, inherited from the K1, allows up to eight patches to be called in a specific order by pressing the +/YES and ./NO buttons - this definitely is useful for live work.

The manual is full of diagrams, although it could still be more informative and better laid out (couldn't they all?), but I don't think anyone will have trouble getting to grips with it. It has comprehensive MIDI data tables (mainly for the programmers) and it even has an index. With just a little knowledge of synthesis you should be able to program your own sounds and create your own Multi patches with relatively little effort.

THE K4R

UNLIKE THE DELAY between the launch of the K1, the K1M and K1r, Kawai have released the K4 and its rackmount version at the same time. The K4r is a 2U-high 19" module with all the buttons on the front panel - so operation is just as easy. It has no pitchbend or modulation wheels (natch), and none of the built-in effects either, but it has six separate audio outputs as well as right/mono and left stereo outs, and the headphone socket is mounted on the front panel for easy access.

The lack of effects is based on the premise that most people who buy rack-mount gear will have an effects unit as well. I could live with that although I still wouldn't say no to having the effects included.

VERDICT

IN SPITE OF anything you may have read about the difficulties of digital synthesis, using and editing the K4 is relatively painless. Full marks to Kawai for this. You won't need an external programmer although I've no doubt a software voice editor will make an appearance soon - and that should make editing even easier.

I'm personally glad Kawai haven't adopted the "workstation" approach and included a sequencer, but then I speak as someone who prefers the power and versatility of a software-based sequencer and the opportunity to pick one of my own choosing.

After the initial honeymoon period with the K4 was over, I donned my devil's advocate hat and voiced the disappointment that the K4 is, broadly, based on K1 technology rather than offering something new. Although if Yamaha can keep FM synthesis going for six years through God knows how many incarnations of instruments, surely there's room in the musical world for a third Kawai VM (DMS?) instrument.

The K1's RRP is still £595 but it can now be seen advertised at up to £100 less (surely a good deal). If you are already a K1 owner I'm not sure I'd recommend that you rush out and trade it in for a K4 (unless you can afford the loss on the difference). But if you've been contemplating buying a K1, I'd think you'll be sorely tempted to beg, steal or borrow the extra for a K4.

And if you haven't yet invested in one of the new generation, PCM sample-based instruments then the K4 is one baby you really must see before spending your readies. Even if you are hovering around an LA synth or even the M1, the K4's filters, ease of programming (an enormous plus), multitimbral capabilities and impressive range of sounds (some mini performances in their own right) demand that you hear it.

And when you pop along to your local music shop, make sure you take your wallet with you because, make no mistake, the K4 will be in demand.

Prices K4, £895; K4r, £695. Both prices include VAT.

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