THEY SAY THINGS come in threes. Well, the Kawai K1 is no exception. When the budget synthesizer was first launched in 1988, it came in a choice of two versions: keyboard (the K1) and module (K1m). For seemingly very little money, both versions offered phenomenal sound-creation potential, and by the end of the year they had established themselves as two of the most sought-after low-cost synths to hit the market in years.

Now there is a third option, in the shape of the rack-mount K1r. The main advantage of rackmounted instruments and effects is that they save all-important studio space - assuming you have, or regularly use, a studio. You do need some kind of MIDI keyboard to play a rack's sounds from, but even if you don't have one, you can still trigger the sounds from a multitrack sequencer.

But sometimes design compromises have to be made to accommodate the uniform size of a 19" wide and 1-unit high front panel. In the case of the K1r it's the joystick that's gone missing. Without it, some editing procedures become more fiddly than on the original K1 and K1m, although the sounds all three produce are basically the same.

The K1r offers a maximum polyphonic output of 16 voices (so you can play up to 16 notes at once) from a "VM" (Variable Memory) tone generator. This, in turn, offers a huge selection of 256 basic waveforms from which sounds can be created. Of these, the first 204 are formed by "additive synthesis" (no, you don't have to know what that means) of the first 128 harmonics (or that), while the rest are encoded samples of guitars, strings, flutes and so on. Up to four of these can be mixed and modulated for each sound. All of the sounds are touch-sensitive, so they play louder the harder the keys of your connected keyboard are pressed, and can be programmed to respond to after-touch if your keyboard can handle it; if it can, this facility gives you the chance to alter the character of a sound by pressing a little harder on a key after you have first struck it.

It is also possible, via the miraculous MIDI connection, to set different sounds to respond to different levels of keyboard velocity. This can be a great advantage in adding expression to a sound. Imagine, for example, that you've layered two different saxophone sounds on top of one another. With the K1r, you could have a muted version set to respond to low keyboard velocity, and a no-holds-barred growling version set to play when the keys are struck harder. So, the harder you play, the louder your saxophone growls - just like the real thing, only you never run out of breath. Up to 32 of these configurations can be saved as Multi patches, easily recalled at the touch of a button.

As it leaves the factory, the K1r comes complete with 64 Single and 32 Multi patches already programmed in its internal memory. Between them, these make a good indication of the range and quality of sounds the unit can produce, and a good starting point for programming your own sounds. The ability to mix sampled attack portions (ie. the initial stages of a sound) with VM synthesized waveforms means it's possible to create very realistic imitations of acoustic instruments, if the fancy takes you. Generally speaking, the K1r excels most at breathy, atmospheric sounds, and is unusually "warm" in tone for a digital synth.

There are also nine drum and percussion samples, similar to those in Kawai's R100 and R50 drum machines. In other words, if you are driving the K1r from a sequencer you can program drum parts as well as bass, strings and melody, and run them all from the same box at the same time. In fact, the K1r has been designed specifically with sequencing in mind. It has a built-in mixer section to control the panning and relative volumes of all of its eight sounds, so you can do as much setting-up on the module as possible.

A synthesizer is only as good as the sounds it produces - in the same way that a synthesist is only as good as the sounds he or she programs. But it helps the latter a great deal if the former makes programming sounds relatively straightforward. A few years back, many digital synths illustrated the limitations of an inaccessible programming system, and since then, manufacturers have gone out of their way to produce synthesizers which are easy to understand and get the most interesting sounds from.

Programming sounds on the K1r appears daunting when you first start pressing the buttons, but give it a couple of hours and things start to look up a bit. Pressing the Edit button enters Edit mode, strangely enough, and then the "ABCD" buttons (which are normally used to select different banks of sounds) double up as "Group Select" keys. Each Group contains a different set of parameters. In Group A you find parameters which affect all four sources equally, such as vibrato and keyboard modes and response curves. Group B is subtitled Frequency, and contains all the parameters that determine pitch. Group C parameters determine the waveform, built from up to four Sources as described earlier. And Group D is the envelope section that controls how quickly sounds attack, how long they sustain, and how long it takes for them to fade away once a key is released.

Usefully, Kawai produce a card that summarises all this and graphically displays the ways in which all the parameters and groups link together. You also get a booklet entitled 'K1/K1m/K1r Wave List'. This is the only way of finding out which of the 256 Sources are which, and even includes graphic representations of the basic waveforms. The list helps you to choose exactly which Sources you want to use, and is another invaluable editing tool.

So ultimately, the K1r's programming system is intuitive and fairly easy to understand. But should you not wish to program sounds on the module itself, there are now a number of software editing packages available for owners of Atari ST computers; the advantage of these is that they let you see what you're doing much more clearly.

The K1r performs well, and has a pleasing sonic character which - as you would expect - is unique to the K1 series. It faces stiff competition in the marketplace from the likes of the Roland D110 and the Yamaha TX series of expanders. Where it succeeds is in its freshness and its ease of use.

And if you've never heard or Kawai before, don't let that put you off. They're one of the longest-established musical instrument companies in Japan, and have been making pianos and organs for decades. Their career in cheap synthesizers has got off to an encouraging start.

KAWAI K1R SYNTHESIZER EXPANDER: £435 inc VAT

INFO: Kawai UK, (Contact Details)