Mark Jenkins looks in depth at the more affordable end of the polyphonic keyboard market

Fairlights and Synclaviers are all well and good, but have one drawback — they're enormously expensive. So let's be down-to-earth for a change and take a look at some more affordable machines, specifically with an eye to deciding how they compete with the more obvious 'budget' polysynths — the Roland Juno 6 and 60, the JX-3P, the Korg Poly 61.

What we're talking about is Home Keyboards, or Personal Keyboards, or Home Entertainment Systems — whatever you want to call them. Straddling the gap between the home organ market and the more general amateur musician, the Casios and Yamahas of this world (together with their increasingly common rivals) can be wonderful first keyboards, learning or practising instruments — or even more, as The Human League, Trio or the Eurythmics could tell you. My career in polysynths started with a Casio 201, now deleted in favour of the 202, and the old black box served well for many moons with its wide selection of stringy and percussive noises, particularly when treated with a bit of phasing and echo. What was (happily) missing from the 201 was an accompaniment section which features in one form or another on all the keyboards examined here, and the use of this sort of system is very much a matter of personal taste — you either love 'em or you hate 'em.

We'll take Casio as a starting point here and wander off into the exotic world of Personal Keyboards which it's been my pleasure (or otherwise) to inhabit over the last week or so, and try to come to a few conclusions at the end of the article.

Casio CT-610

£395

Casio invented the home entertainment single keyboard, pausing only to create a few more completely new markets with the VL-Tone, the machine nobody would ever have imagined they wanted until Casio built it. Since those days there have been a constant stream of new products ranging down in size to the microscopic (but polyphonic) VL-5 and up to the latest Symphonytron dual-manual giant. Casio have introduced arpeggiators, inverted envelopes, rhythm units, digital recorders and, latterly, stereo sound and chorus units. What hasn't changed in all this time is the basic method of sound generation, which still depends on two digitally-defined waveshapes (a 'vowel' and a 'consonant') which combine together to give a degree of movement and realism in the sounds.

The term 'degree' is used advisedly, because after the initial thrill of owning an eight-note polyphonic synth with 29 sounds costing a mere £200 or so died down, it became clear that the nature of the sounds just wasn't on a par with any kind of professional synthesizer or even string machine. Certainly a few bands such as the Human League, Eurythmics and Trio used Casios to great commercial effect, but they were only used sparingly and any attempt to base an entire composition on Casio sounds resulted inevitably in an overall texture which was less than professional.

Things have improved a little with the introduction of stereo chorus, and some models such as the CT-1000P have a vast variety of user-definable envelope shapes. We looked at one recent model, the CT-610, which boasts the former facility but is fairly average among Casios in terms of sound selection.

The CT-610 comes in a choice of two finishes, a high-tech chrome style or a simulated wood 'front parlour' finish. Combined with a Casio stand it wouldn't look out of place either on stage or in the plushest studio, and because it has built-in speakers and amplification it's ideal either for home entertainment, composing or practising. There is a quarter-inch headphone socket, Left and Right line outputs, a socket for an optional Foot Volume Pedal and Sustain Switch and a rear-panel Tuning pot. The mains lead is detachable (a professional touch) and the heavy rubber feet and general smart finish add up to a well-constructed piece of equipment. If you want to play from sheet music there's a pair of sockets for the music stand supplied.

The specification, as mentioned, is fairly typical; 20 sounds on 10 push-buttons with an eleventh A/B selector, 12 rhythms on six switches with a seventh A/B selector, automatic Bass, Chords and Arpeggio with Synchro Start. The machine has three sliding volume controls, for Percussion, Bass/Chords/Arpeggio and total output. In addition there's a sliding Tempo control and Fill-In button together with a number of options for the accompaniment — constant or repeated chords which can be played conventionally or with only one finger and a choice of two bass/arpeggio patterns for each respective rhythm.

The polyphonic sounds themselves are the usual mixture of good, bad and middling. The stereo chorus and sustain add a lot to all of them, of course, particularly to the violin and cello tones which become much more reasonably thick and phasey. Some of the wind instrument tones, such as flute and oboe are satisfyingly clear and sharp, and the electric organ is pleasantly clicky although the church organ lacks power and depth. 'Funny' wasn't particularly amusing and 'Cosmic Tone' wasn't particularly cosmic — more like a thin, synthesized clavinet.

The percussion voices are good, with a clear snare and metallic cymbal and a reasonably deep bass drum. The fills are well composed although some of the bass accompaniments (such as that for Bossa-Nova) are a little idiosyncratic. The chords work on the bottom octave-and-a-half of the keyboard and steal notes from the top part of the keyboard, using an inoffensive harmonium-like tone. The two speakers produce a fair enough volume and the keyboard action, while not suiting a trained pianist, is fine for anybody used to organs and synths or just starting with keyboards.

Korg SAS-20

£599

Korg's representative in our article comprises a first attempt in the 'Personal Keyboard' field, and as such is pretty successful. In addition to including all the standard and familiar features of the field it introduces a few new ideas including the most versatile accompaniment section around. Whether or not this is a good thing for the more experimental musician is open to question of course, but the Korg has a decent selection of sounds which can be played in the good old-fashioned way — with your fingers.

There are 12 polyphonic sounds (fully polyphonic incidentally, giving a nice thick texture to long runs with the sustain switched on) on six switches with a seventh selector with LED top/bottom indicators. The sounds can be thickened up with a stereo chorus and although showing few signs of the 'innovative synthesizer technology' frequently mentioned in the handbook they're not too bad, particularly the string and brass ensembles and the electric piano which are pretty realistic. The Clav. Synth is disappointing though, while the Vibraphone is nice but has sustain on it whether you want it or not.

The accompaniment section has the usual mixer controls for the percussion, bass and chords and a sliding Tempo control coupled to a 4-LED Bar Counter. There are 16 rhythms such as Slow Rock 1&2, Pop Rock 1+2, Waltz and Shuffle and a more general 2-Beat and 3-Beat, but these are re-programmed when the SAS cartridge is changed. This is a ROM pack which fits on the back of the keyboard and is aimed towards a certain style of music — Easy Listening, Jazz Fusion and so on — with all the rhythms and accompaniments being re-defined to match. The basic idea of the Super Accompaniment System is that the backing chords are defined by the right-hand melody, the keyboard's built-in microcomputer looking at the melody notes and picking a suitable chord. This may sound a little complex, but according to the handbook "in spite of the incredible number of songs in existence, they can all be classified in four modes according to the type of melody or chord progression". In practice there aren't too many problems associated with the system although you might get the occasional funny if you play too fast or too 'imaginatively'. The backing chord and arpeggios selected by the Super Accompaniment System are played in a variety of percussive or sustained sounds resembling pianos, harpsichords and guitars. All these sounds change according to the SAS cartridge used.

The SAS-20 has a few more special features intended largely for the home entertainment market. These include a Transpose LED display which changes the pitch of the whole keyboard for the benefit of vocalists with a limited range or keyboard players who don't want to have to learn all sorts of different keys (shame). Also there's a Microphone mix slider which feeds in the input from a back panel socket, allowing the player to amplify his voice over the built-in speakers or whatever amplification system is being used at the time.

Other back panel features include a headphone jack, optional volume pedal jack, a pair of phono line out sockets, a Tune pot and the socket for the SAS cartridge. The mains lead is a detachable 2-pin and the overall finish is an unusual metallic grey and beige, with a slimline feel coupled with a rather unusual depth.

The SAS-20 gives a wide range of playing options. The Super Accompaniment System itself only allows monophonic playing on the top half of the keyboard, but since there's so much more going on at the same time this isn't necessarily too limiting. If you do want to play a little more, the normal accompaniment mode gives you polyphonic playing over played or one-finger chords, and of course the use of rhythm, bass and arpeggios is mixable. Finally, it's possible to add a chord to each melody note played when either of the accompaniment modes is in operation. This can be quite useful for some pieces and certainly thickens up the overall texture, but if you play clumps of chords with the 'Melody Chord' switched on the result can be quite a mess; it's a useful feature though and can give interesting Keith Emerson-like melody textures.

Yamaha PS-400

£235

The PS-400 differs from the other keyboards examined in this article in terms of scale if not other facilities. As part of the Portasound series it's built to a half-size scale which gives it miniature keys as seen on the CS-01 synthesizer, but this needn't necessarily be a drawback and in fact can be a distinct advantage. Since these home keyboards are likely to be used by the more serious musician for practice and rehearsal it's often a case of 'the smaller the better', and a polyphonic keyboard which can be carried in one hand can be a godsend. The PS-400 is in fact 62cm long and weighs 3½ pounds.

The keyboard's three and a half octaves and has the usual accompaniment facilities on the lower octave. There are 10 8-note polyphonic sounds including organ, piccolo, harpsichord, piano and vibraphone, with optional sustain of about two seconds. Some of these sounds are quite outstanding for a small machine, at least as good as the larger Yamaha keyboards such as the PS-55. Organ in particular is very striking, with a convincing key-click, harpsichord is clear and metallic and vibraphone has a gentle tremolo for added authenticity. The strings and brass aren't too bad but need a decent chorus unit.

What does let the PS-400 down a little is the rhythm unit, which is reminiscent of the Casio VL-Tone (yes, that bad). The 'toms' and cymbals have an annoying tuning to a high pitch which interferes with almost any piece you'd want to play and the various cowbells and Latin instruments used in Rhumba, Samba and other patterns are equally irritating. This partly spoils the fact that there's a nice four Bar Variation facility which inserts some pretty heavy fills. The accompaniment section can be Synchro started with the lower keyboard and of course there are also Arpeggio and Bass/Chord facilities. Each accompaniment pattern has two variations and single finger or fully fingered chords are possible; the pitch of both accompaniment and keyboard can be changed with a transposition dial on the left-hand side.

As with many of the other keyboards featured here there's a 'Duet' function which duplicates the lower keyboard chords on an upper keyboard melody note. This is useful for thickening up harmonies but is definitely over the top if chords are played on the top of the keyboard. The last major function is the Chord Sequence Memory, which can store a chord progression with some of the upper keys being used to specify chord length, ties and 3/4 time.

The PS-400 can be powered from batteries, a car lighter socket or a mains adapter, and so is ideal for rehearsing or composing. The sounds aren't bad at all and the rhythms/fills are suitable for composing if unacceptable for recording. A phono line out socket and optional volume pedal input together with headphone mini-jack and 12V DC input complete the picture, together with a smart and durable carrying case included in the asking price. Overall, a neat and versatile package that could solve a lot of problems for the musician on the move.

Technics SX-K200

from £435

The Technics SX-K200 has the built-in advantage of looking like the flight deck of the USS Enterprise and boasts some suitably technological facilities. Its black and silver styling makes it more closely resemble a piece of hi-fi equipment than a musical instrument, but the layout is logical and useable. The only disadvantage is that all the control buttons are silver and it's not too easy to identify them in a hurry!

The SX-K200 could more accurately be called an ensemble keyboard than a simple home entertainment unit since it has several independent sections. There are eight Poly Orchestral Presets (Organ 1/2, String/Brass ensemble, Accordion, Guitar, Piano and Harpsichord), six Solo Synth Presets (Clarinet, Panflute, Trombone, Whistle, Trumpet and Cosmic Wah), percussion, bass, arpeggio and chord sections, with individual mixing feeding into a master volume slider. The entire instrument can come under the control of a digital RAM memory pack which clips into a recess on the top of the instrument, and which has the capability to act as a 'Full Band Setting Computer' — memorising not only chord patterns but also sound selections and percussion patterns.

The polyphonic sounds are quite satisfying, with a good degree of movement within each sound and even further possibilities using a tremolo on the Organ settings, a celeste/chorus on the string and other settings and selectable sustain. It's possible to play the polyphonic and monophonic sounds together with the solo synth giving high note priority, and as the relative volumes can be balanced a wide range of textures and playing styles are available. The synth sounds themselves are pretty clear, the Panflute being particularly attractive and the Cosmic Wah being quite similar to a thin monosynth setting.

It's the percussion sounds which are outstanding though, since they're all created using a PCM (Pulse Code Modulation) system similar to digital recording which in effect gives sampled sounds. The snare drum is very impressive and the toms have a distinct 'bend' to them, something you won't hear on any other keyboard examined here. The cymbals also benefit from this system, with a good balance of metallic and noise effect instead of leaning too far one way or the other. The rhythm patterns are well composed and there's a Fill In/Intro button which gives different variations at the start or in the middle of a tune, with the option of having a fill automatically on every eighth bar. The rhythms include Rock, Disco, March, Swing and Waltz, and can be started at the first touch of the lower keyboard.

The bottom octave-and-a-bit of the keyboard offers the usual accompaniment features including one finger or fully fingered chords which can be transferred to top keyboard notes, Transpose, locked chords and a chord computer. The Chord Computer can store up to 50 chords using some of the top keys of the keyboard as controls allowing editing, specifying chord length and programming of an end point. The chords programmed can be reproduced in synchronisation with the rhythm section and with any of the selection of rhythmic bass and arpeggio patterns available.

The Full Band Setting Computer uses a RAM Pack to store not only accompaniment details but also the actual sound settings used, although it still doesn't memorise melody lines which can be played manually over the top. Blank memory packs are available from Technics as are pre-recorded example packs — each pack storing up to eight tunes.

There are rear panel phono sockets for stereo inputs together with a jack socket for an optional volume pedal and a headphone socket. As usual there's no clock output for the rhythm machine section, which is a shame as it's so impressive, but apart from that the Technics is undoubtedly one of the best home keyboards. The polyphonic sounds owe more to top-of-the-range organs than to synthesizers but that means quite a lot these days with an increase in the critical faculties of the average organ owner. Definitely one to check out.

Seiko Digital Keyboard

£449

Seiko's first foray into the world of portable keyboards is a peculiarly mixed bag and by far the most difficult to review of the instruments examined here. This is because it is a modular system which ranges in its various combinations from the pretty ordinary to the highly unusual. The possible constituents are the DS-101 Keyboard — the DS-202, a larger and more versatile keyboard — the DS-310, a digital synthesizer add-on — and the DS-320 Digital sequencer, which also takes over control of the keyboards' built-in rhythm sections.

The DS-202 keyboard resembles a Casio or Yamaha portable, with 10 polyphonic sounds, eight rhythms, bass and chord accompaniment, chorus, delay vibrato and twin speakers. The polyphonic sounds include Harpsichord, Piano and Electric Piano, Vibraphone, Brass and Strings, with a choice of two sustain lengths (about a second and about four seconds), two chorus depths/speeds and a vibrato delay slider with fixed depth.

The lack of full variability may seem a disadvantage, and in fact it is, but when all the facilities available are switched in things begin to get interesting. Particularly so when the keyboard is split as it can be at a point just below the middle of its five octaves — for instance Strings can be assigned to the lower half and Flute to the top half. There are the usual accompaniment facilities including auto bass and one-finger chords, no sign of the dreaded auto-arpeggio, and the major disappointment is that there's no Fill-In function on the percussion, which ends up being pretty monotonous with rhythms like Latin 1 and 2 using up several of the limited number of options available. With the chorus and sustain on, the Harpsichords and strings are very usable, the pianos acceptable, the jazz organ boring and the brass passable. Keyboard Split makes the whole thing more interesting, with combinations of two sounds often more than-making up for any deficiencies in the individual sounds. A sustain switch and volume pedal can be added and there are a number of power supply options, but the major problem is price, being £585 recommended. Without large shop discounts the Seiko is going to lose out against the already well-established Casios and Yamahas.

The whole thing becomes more interesting when the DS-310 Digital Synthesizer is plugged onto the back of the keyboard using a multiway connector. The 310 has a large LCD display with a block diagram of harmonics and a representative chart of envelope types. To create a sound the synth is first switched to 'Spectrum' and to one part of the envelope, Attack, Sustain or Release. The level (from one to 15) of any of the 16 harmonics available can be specified, and these mixtures can be completely different for each stage of the envelope. There are four envelopes giving different emphasis to the Attack, Sustain and Release phases, and once an envelope is chosen the exact length of each segment can be stored from 0 to 10 seconds. Having decided the harmonics and the length of the envelope stages, four complete sounds can be stored; these can then be mixed with the preset sounds on the keyboard and treated with the chorus and delay vibrato.

The overall result can be quite stunning and can be compared to a computer synth such as the alpha Syntauri simply because the method of defining sounds is very similar. Digital sounds aren't at all like analogue sounds — although there's a vast range available they're quite distinctive, subtle and gentle rather than harsh and powerful, but with undertones of forcefulness reminiscent of vast church organs or string sections.

It's possible to simulate the classic synth 'filter sweep' sound by programming high harmonics in the attack phase, middle harmonics in sustain and lower harmonics in the decay. It's more subtle than a Prophet or similar analogue synth though, the kind of sound which only advanced synthesists become interested in, which is why the system is difficult to review — it's hard to identify the market at which it's aimed. The digital synth retails at £295.

Lastly the DS-320 Digital Sequencer, which can store four melody lines and one chord sequence, dump to a RAM pack, synchronise with the rhythm unit, display notes on a musical stave and accept programmes in real time or step time. Comprehensive editing and composing facilities exist and it's possible to play over the sequence on the keyboard. Again, it's an expensive addition at £329, but can create some interesting patterns on digital sounds.

The DS-101 keyboard at £435 is compatible with the digital synth but apparently not with the sequencer, and offers 12 imitative and four digital sounds with sustain, delay vibrato and transpose. The Seiko system has a computer interface (not identified but presumably RS232 or similar) which again is a real professional synthesist's feature and hardly likely to appeal to the home entertainment keyboard market.

The Seiko with all its limitations and capabilities is by far the most interesting (and frustrating) instrument examined here, a major stumbling block being the price — £1205 recommended for the whole system, well into the semi-pro polysynth bracket. The schizophrenia of a keyboard which sounds like one of the cheaper Casios one minute and like a baby Wave 2.2 the next after the flick of a switch can be alternately confusing and delighting, and it's almost impossible to say who might be confused and who delighted. This is really one case where it would be worth going along to a stockist and finding out for yourself.

Conclusions

The home keyboard market overlaps in unusual ways with the world of professional or semi-professional keyboards. Many bands starting off can't afford the better-known polysynths such as Junos or Korgs, and the home keyboards can offer a solution even if it's only a temporary one; alternatively the rhythm and accompaniment sections make the Casios, Yamahas, JVCs and so on ideal for learning and entertaining in the home.

The accompaniment sections in particular are becoming more and more sophisticated to the point where the 'performer' no longer has much to do. This trend is particularly noticeable on the Technics keyboards with their 'Full-Band Setting Computer' memorising every note and switch position via a RAM pack. The ultimate intention of this facility is for one Technics owner to compose a piece and to send a RAM pack only to another owner for playback and criticism. The advantages of this system as opposed to a cassette tape of a performance are dubious; the sounds can be changed admittedly, but only if you have the right keyboard for playback in the first place.

Accompaniment sections on the Casios and Yamahas are fairly similar. Some of the larger Casios have programmable chord progressions and the Seiko has a sophisticated sequencer which comes as an option (ie, it costs more). The larger JVC keyboards also have programmable chord sequences, and this sort of facility coupled with a rhythm section can be quite reminiscent of more professional sequencer/drum machine combinations. The use of automatic arpeggios in anything other than easy listening music is strictly limited however — after a couple of songs the novelty begins to wear off.

Percussion sounds vary in quality from machine to machine, although none of the machines examined was really dire in this department. The outstanding instrument in this area was the Technics, which uses PCM sampled sounds on the percussion section and is arguably the closest you'll get to a digital drum machine (though not programmable) for a few hundred pounds. One big disadvantage of home keyboards is that, not having the synthesizer musician in mind, there are no clock outputs to synchronise the rhythm sections to sequencers and other machines.

On the quality and nature of the polyphonic sounds themselves, let it be said straight off that none of the keyboards here will sound much like the least expensive true polyphonic synth. The stereo chorus in the majority of larger home entertainment keyboards nowadays will give a little life and movement to the sound, and in the case of the JVC and Technics will allow a reasonable string synthesizer impersonation. Overall though the sounds available derive more from the home organ than the synthesizer world, with the Technics standing out because the Technics organs are so unbelievably sophisticated — veritable Concordes of the organ world!

The one exception to this is the Seiko with the Digital Synthesizer added. This really shows up any other programmable home keyboard (such as the Casio CT-1000P) as the Harmonic system used can give convincing PPG Wave 2 impressions as well as more familiar polysynth twangs denied to all the other home keyboards. The complete system is quite expensive though, and when considering any of these keyboards (unless the accompaniment section is a necessity) it's as well to keep in mind the market or even secondhand price of a basic polysynth — about £450 for a second-hand Juno 6.

One option is to buy a home keyboard of the kind examined here and invest a little extra cash in a decent flanger or phaser (about £60) and a reasonable monophonic synthesizer for lead lines (such as the Roland SH-101 or Moog Rogue for around £225). This would give a versatile combination of chordal and monophonic sounds with the use of a rhythm backing if required and quick access to a (limited) number of polyphonic textures, which would have a reasonable degree of life and movement with discerning use of the effects mentioned. As in all things, the final choice depends on exactly what sort of music you want to play and how much you're prepared to spend. There's no substitute for actually playing some of the machines mentioned here, and the Casios and Yamahas are easy to find while some of the other machines may be more easily located in specialist organ shops than conventional music shops. Above all, remember that it's musical imagination and not instrumentation that counts, and a good little 'un... well, you get the idea.