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Kawai SX-210

Before going any further, I think I should clear up any misunderstandings regarding the brand name under which this instrument is sold. Kawai are, I believe, the world's largest (in terms of value-of-sales) manufacturer of keyboard instruments. In Japan they used to market their synths and more group-gear orientated lines under the Teisco label, which, strangely enough, was the name of the original Kawai company. Now, some bright spark had the idea of setting up a world wide Teisco division and thus all the 'group-gear' products — keyboards, amplifiers, mixers, effects, etc, bore this logo.

You don't need me to tell you that Teisco isn't the most attractive name under which to market a quality product, especially as the company already has an established and respected name; so now all Kawai products are sold as such, with 'KAWAI' clearly emblazoned across the front and rear panels.

Incidentally, Kawai's 'group gear' products are marketed in the UK by John Hornby Skewes and Co. Ltd, Leeds; whilst the organs and keyboards continue to be handled by Arthur Butler & Co. Ltd, Bournemouth (what a pair of unlikely names).

Kawai's synths have always impressed me, especially the S-100P (still the best preset monophonic around, and it's been around for 4-5 years now), however, for some reason their products have always been too expensive. I don't know why this is, I'm sure it's not the case that someone along the line is being greedy and making too big a markup; it just boils down to the fact that the manufacturing cost for the former products was too high, probably because Kawai's group gear market was comparatively small.

But, things are different with the new SX-210, because this is a bargain, a snip, a knock-down. The SX-210 has a recommended retail price of just £999. Another thing to bear in mind when reading this review is, that in order that we can bring you news of this remarkable unit at the earliest opportunity, we had to test a pre-production run machine (actually it was the one that was at Frankfurt) and consequently Kawai may have made a few 'corrections' and amendments to the unit by the time it is in the shops. So, some of the herein criticisms of the SX-210 may not be relevant in the final event — but you should check these out before purchasing; there's no harm in us advising you what to look out for.

The SX-210 is an eight-voice polyphonic programmable synthesiser which utilises the Incrementation system of parameter manipulation. This is the control system employed by Moog with their Source, New England Digital with the Synclavier, and if you cast your mind back to our March 83 issue you will find that the new Korg Poly 61 is also based around this method.


Incrementation means lower costs. That's really the only reason it is employed, although as we shall see, with the SX-210 it does mean that specific parameters can be much more accurately defined, and also their value represented digitally.

For those of you who don't know what I'm talking about, and who think that incrementation is some form of DHSS Earnings Related Benefit I shall explain. The rest of you can skip the next two paragraphs.

In days of yore, the controls on the front panel were hard-wired to the respective circuits, thus the filter resonance pot (a variable resistance that controlled the amount of feedback applied to the filter circuit) was actually connected in to the circuit. Nowadays, with microprocessor-based synths, all the control elements on the front panel, be they switches or pots, are scanned by the processor, and manipulated digitally. These digital codes are then translated back into control voltages and used to specify a set of parameters; so in the case of the filter resonance, a voltage controlled resistive element is incorporated in the feedback loop and the control voltage used to define the exact effect. In a processor-based system all elements have to be voltage controlled.

Now as there is no direct link between a control surface and its circuit element, the control's effect is determined by the operating program of the processor. It is in this way that Oberheim can conveniently offer a second page mode which assigns all the front panel controls new roles, simply by amending the software. If this system is taken a stage further it follows that only one control knob, and a way of specifying which parameter it is to control, is needed. This is the Incrementation method — which in its refined state works as follows: a parameter is selected (filter resonance); its current value is depicted in display (0 to 99); and by advancing the incrementor control that parameter is edited to a new value; another parameter can then be selected and amended accordingly. A little thought will help to realise why the control element (if it is rotary) must have an infinite action, i.e. can be continually rotated. The processor needs to detect how much and in which direction the control has been deviated. Note — incrementation should not be confused with quantisation.

The SX-210 utilises a rotary incrementor and the whole system is ten times better than the one used on the Poly61. The trouble with these devices is that they can be slow to use; for example the Korg machine requires the player to first select Program or Edit mode, then type in the parameter code number, and then to use 'Up' and 'Down' edit the setting; this is messy, and awkward in the extreme. With the Kawai SX-210, each parameter has a momentary LED switch, which when hit causes the incrementor display to show the value of that setting and then it is ready to be altered — much quicker, in fact, it is virtually as quick as using a conventional control system, but with the advantage of being far more accurate.


This is an eight-voice instrument with 8 DCOs, 8 VCFs, 8 VCAs, 8 VCF-EGs, and 8 VCA-EGs. If we look at a voice we find it thus: the DCO provides ramp, square, and/or pulse (width modulatable) waveforms at 16', 8', and 4', and in addition there is a sub oscillator one octave down that produced an interesting pulse like waveform. There is a noise generator (N.B. Korg). Incrementable (see O.E. Dictionary — a big one) parameters are indicated by grey momentaries, switch parameters, e.g. waveform selectors, are black.

The sound sources are thence fed to the VCF which provides 24dB/octave low pass attenuation. The filter can be set to track the keyboard (variable), and the filter set into oscillation by increasing the resonance, however, the tuning of the filter isn't quite stable enough to facilitate accurate filter 'playing', especially if also utilising filter envelope modulation. The envelope generators are both ADSRs, obviously with one for the timbre, the other for the amplitude. To round off the voicing circuitry there is a static high pass filter which is always a useful extra, and especially so with this machine. At this stage the voices are combined together and routed, if desired, via an ensemble circuit to further enhance the sound.

The SX-210 is equipped with just one LFO, but this can be used to produce ramp, triangle, and square waves, and these can be inverted if required. An inverted ramp up wave becomes a ramp down; the triangle wave is unaffected by inversion; but surprisingly inverting the square wave has a useable effect. The LFO is primarily employed to modulate the oscillators' frequencies and when a square wave is used a trill effect is produced oscillating between the fundamental pitch and a note above it (depending on the degree of modulation). When the square wave is inverted, this trill effect is shifted so that it occurs between the fundamental and a note below it... interesting.

The LFO can also be used to modulate the VCF and the VCA, it has a delay facility and in addition it can be used to trigger the envelope generators, which is a surprising extra for an instrument of this price.

Kawai synths are 'famous' for their Bender facility. This is a different effect to that of the Roland Bender, which is their performance control lever. Here the Bender introduces a sweep up to the fundamental pitch as the note is played. It is this facility that makes the SX-210 very good at producing choral, vocal and whistling type simulations (a la Tomita). In fact, it is possible to produce an uncanny choir effect with the SX-210 — a combination of the filter characteristics, the high pass filter, and the use of the Bender makes this attainable.

The overall character of the Kawai's sound is one of brightness and clarity, it is not a particularly full sound, nor is it brassy like several synths today (especially American ones), but it does have a slight colouration to it that makes it well suited to today's contemporary musician.

Internal Construction.


The keyboard is of the five octave C scale variety. It is a nice keyboard, though with Kawai being the world's largest keyboard manufacturer, one would expect them to have got it right by now. It isn't touch sensitive, however, nor is it splittable, but then one wouldn't expect such features on an instrument in this price range.

The voices can be assigned to the keyboard in one of three ways. 1) Poly 8 — this is really normal mode, with up to eight keys playable simultaneously. 2) Poly 4 — here two voices can be layered on top of one another to enhance the sound. Both voices have the same sound, but an interval can be programmed between the two voices via the keyboard, thus you can have one oscillator producing the root, and another a harmonic 2 1/2 octaves up (say). I found that if you set up an interval of above three octaves funny things start to happen at the top end (check this one out). Kawai have made a big mistake here — there is no way to layer two oscillators on top of one another in unison, but slightly out of tune with one another in order to produce phase cancellation and thus timbral movement. The pitches are supposed to be shifted slightly in this mode, but they don't appear to be, and as they are DCOs, deriving their pitch from a single oscillator, the sound is annoyingly flat and lifeless. A small software change should be made to amend this. 3) Mono — this causes all the oscillators to sound simultaneously; again it is possible to programme each oscillator at a different interval, thus generating quite an impressive monophonic voicing.

Keyboard glissando, the slewing between notes in quantised semitone steps and portamento, continuous slewing between notes, can be selected and programmed at various rates, and infinite sustain can also be activated if desired.

Performance Controls

I'm not a great fan of the centre sprung lever, but the SX-210's lever has a rather nice action to it that appeals to me. The amount of pitch shift that a full scale bend inflicts can be set using the incrementor, though for some ridiculous reason the maximum shift is just +/- a fifth, it should be at least an octave. LFO modulation is introduced via a momentary 'Start', set alongside the lever. This is a rather interesting configuration. Normally the LFO is permanently routed to its particular ports, however, it can be disabled and triggered only when the LFO Start button is held — this may sound rather unexciting, but it seems to work well.

Programmer and Voice Identification

There are 22 On/Off, and 24 variable parameters to be stored for each voicing, with each of the latter requiring one percent resolution. 32 memory locations are provided arranged in 4 banks of 8 (A1 to D8) for just such a purpose — a fair enough number, which of course can be extended with the use of the cassette interface. The SX-210 has one unique feature which may be invaluable to some users, every memory location can be assigned a 6-letter code name, so when calling program C4 (say) which might be a String sound, it is possible to preprogram the word STRING 2 into the "Name Memory" so that every time C4 is re-called the name appears in the 6 x 16 segment voice identification display. The keyboard is used to set the name with 51 of the keys providing different characters (letters, numbers, punctuation, and operator symbols). Personally I think that this is a bit of a gimmick and would suggest that Kawai do away with it and reduce the price accordingly, however, I can see that some people would find it extremely useful, especially when recalling old programs from cassette.

The SX-210 lacks interface ports in a big way. Stereo audio outputs are provided, the stereo coming from the ensemble circuit. A Headphone outlet is to be found on the rear panel, along with cassette interface sockets and a memory protect switch. But otherwise there's nothing — not even a sustain footpedal socket. Surely Kawai could have at least provided one of these?


The SX-210 looks good, and feels good to use. The casework (880 x 400 x 128mm, 12.2kg) is attractively designed, extremely well made (being primarily an acrylic lacquered metal with wooden end cheeks), and ergonomically designed, although the master tune control knob looks well out of place. On the model I scrutinised, the incrementor control knob didn't function very well, with the numbers jumping about rather erratically if the knob was turned quickly, although I'm sure this will be corrected on the production machines. Otherwise, with the exception of an annoying aliasing of the ensemble circuit, the instrument performed admirably.

Internally the pre-production machine seemed a little ragged, with bundles of cables tied together as opposed to being ribboned up, and various mods and links inserted. But no valid comments can be passed as this wasn't the final machine.

I think that if JHS promote this product properly it will do very well for them and Kawai. If the Kawai designers do something about the fine tuning of the layered voices in Poly 4 mode, then the SX-210 will be one of the best poly synths around, certainly the best value. Even as it stands I really prefer it to the Poly 61 (the main rival) but Korg do have better promotion and marketing than Kawai in the UK so no doubt the Poly 61 will sell better. This is a refreshing instrument with a refreshing sound — get refreshed!

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Aria U60 Deluxe BBS

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Studio Sound Techniques

Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Jul 1983

Gear in this article:

Synthesizer > Kawai > SX-210

Gear Tags:

Analog Synth

Review by Dave Crombie

Previous article in this issue:

> Aria U60 Deluxe BBS

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> Studio Sound Techniques

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