Like several other members of the Siel range, the Cruise has been available on the Continent for some two years or so, but is only now receiving proper distribution in the UK. Broadly speaking, it's a preset synth with both mono and eight-note poly sections, a splitting facility that allows the keyboard to be divided equally between the two, and a mild degree of control over some of the sound-generating parameters.

In some respects, the design of the Cruise shows its age. It possesses few of the innovations displayed by some of its newer rivals, an arpeggiator or MIDI interfacing, for instance. The importance of these innovations will vary from user to user, of course, but in view of the fact that the Cruise is to a large degree designed as a 'performance' instrument, sequencing and the like are hardly likely to be uppermost in the minds of many prospective purchasers.

The Cruise is a deceptively light instrument, due mainly to its construction which employs a good deal of plastic; only the control panel is metal. The keyboard is four-octave C-to-C (when will the manufacturers start giving budget poly buyers a decent sized keyboard?) and has an excellent feel that is both light and positive. The controls can be divided into four sections: mono, poly, master, and performance.

Taking the mono section first, this comprises ten toggle-switches to select the desired setting, with an eleventh to choose between PRESET and FREE modes, more of which anon. There's also a vibrato on/off switch and a series of eight slider pots vary some mono parameters, notably ADSR, VCF cutoff and resonance, and depth and speed of the aforementioned vibrato.

All the presets have been given names (piccolo, sax, etc.) by the manufacturers, none of them terribly accurate, though I suppose they serve a purpose. Contrary to initial appearances, control of some parameters is still possible even when in PRESET mode, though precisely which parameters depends on the voice selected. So that you can see these at-a-glance, however, red LEDs above each parameter slider glow instructively as each voice is chosen, a feature repeated in several other areas of the Cruise's design. Moving on to the FREE mode, this is something of a misnomer in that the only additional control it affords the user is the opportunity to vary VCF resonance.

Unfortunately, there are no memories in to which the user can program his favourite settings in FREE mode, although with so few parameters capable of adjustment, it's a limitation that can be tolerated in most circumstances. Generally speaking, the most impressive sounds in the mono sections are those that combine a slow attack with, say, a footage of 8' or 16' (footages are indicated above each preset's red LED; they vary from 4' to 32', giving the Cruise quite a reasonable octave-range for a machine in its price category).

The fact that the mono voices are not mixable does impose certain limitations when this section is used in isolation, but a further problem that might be significant is the lack of keyboard tracking. This omission is presumably a cost consideration, but it does mean that, with the sawtooth-based sounds in particular, high notes can be an awful lot louder than low ones. One redeeming feature however is the mono section's vibrato, which has an excellent range of adjustment and suits most of the preset voices well. Whatever you may think of vibrato as an effect, there's little denying it adds to the realism of the Cruise's mono sounds, so long as a little care is exercised when using it.

But if the mono section disappoints slightly (and I don't want to appear too harsh; some of the voices are excellent, it's simply the variety of voicing that's lacking) the poly section more than compensates. It's split into four sub-sections: brass, strings, reed, and piano, and this time the nomenclature is a little more instructive.

The reed section is next, and this incorporates three voices: accordion, which sounds a little bit too much like a car-horn for my liking; musette, which is an octave up and has built-in rapid vibrato; and the extremely effective church organ, a splendidly deep, resonant voice capable of passable imitations of some of the great French cathedral diapasons.

Lastly, the piano section comprises a further three presets, of which clavichord and honky tonk are a little thin and metallic and need additional delay to make them sound convincing, while piano itself is an excellent, mellow 'upright' version of a Yamaha electric grand.

Unlike the mono section, the poly voices are wholly mixable, not only within their respective sub-sections but also with each other, making a combination of as many as ten different polyphonic sounds possible. Actually, this latter isn't nearly as bad as it sounds, and it's the poly section's mixability which is really the key to the Cruise's success.

The chorus unit (I just can't get used to calling it an animator), standard on the strings as already mentioned but optional for the remaining three, is a little noisy in operation, but this is only really noticeable if you're using the piano section in isolation. Like the mono section's vibrato, it's a well-conceived device that's variable over a usefully large range. Of the various combinations available with the poly section, reed/strings are particularly effective, or alternatively, why not try all four sections together?

Brass has two voices - trombone and trumpet - but the one is simply an octave-lower version of the other. Brass sound is also governed by 'resonance' and 'crescendo' switches and by two slider controls varying attack-time and cutoff. 'Resonance' adds a rather unpleasant 'wah' to the attack, while 'crescendo' is simply a slow-attack preset that obviates the need to adjust that parameter manually. The attack control has a limited but nonetheless realistic range, while increasing the cutoff frequency makes both brass sounds more synthetic, à la The Human League circa 'Marianne'.

The strings section is permanently and irrevocably linked to what Siel rather quaintly term an 'animator' or what you and I would normally call a chorus unit. Again, the section is divided into two voices - violin and cello - one octave apart, while a third toggle-switch marked 'percuss', brings in a none-too-impressive sharp attack: after all, how many stringed instruments can you name that have an attack time of less than 0.25 seconds? Fortunately, two sliders vary both attack and decay times (assuming) you're not using the 'percuss' switch) and this gives the string section a pretty useful range.

The master section controls the relative volume-levels of the mono and poly sections, while two separate toggle-switches determine which half of the keyboard is assigned to each section if the user has selected split-keyboard mode, the latter being accomplished with the same switches. Either section can be assigned to either half of the keyboard, increasing considerably the Cruise's versatility. With judicious use of the level controls, some glorious atmospherics can be achieved with, as just one example, piccolo at the upper half of the keyboard and strings and piano at the lower. The only limitation is that such splitting only gives you two octaves to play with for each voice, but such is the price you must expect to pay if you want a keyboard that can perform the functions of two or three machines in one compact package.

To emphasise the Cruise's performance versatility, Siel have incorporated a performance section at the left-hand side of the keyboard, though the two most significant controls - a portamento slider and pitch-bend knob - work only on the mono section. I found they worked well enough, though in practice the Cruise is such an expressive instrument that for much of the time they were superfluous.

Of considerably more value are the foot-switches that come as standard and plug in to quarter-inch jack sockets (DIN for the volume pedal) at the rear of the instrument.

The decay pedal works extremely well in emphasising short piano passages, for example, without the need to free one hand from the keyboard in order to adjust the relevant slider. The 'keyboard' pedal switches the poly side to mono when the unit is in split-keyboard mode. Also useful.

Clearly the Siel is an instrument of some subtlety. Its sounds are clear and delicate, due in no small measure to the employment of DCOs for sound-generation, while the keyboard action encourages fast playing. The Cruise seems to have been developed in something of a technological vacuum and is therefore not directly comparable to any other keyboard on the market I can name. Yet despite its place on the fringe of synthesiser development, it's an impressive piece of work that few who play it for any length of time find easy to ignore.

It has its idiosyncracies: no voices selected at switch-on, lack of an overall level control, string sounds that don't quite decay for long enough, but these are far outweighed by its good points - its LED indication, the action of its switches, the versatility of its split-keyboard function, its stereo outputs, and above all, the sheer panache of some of its sounds.

Unusually for a preset synth, many of its finest points only become apparent after several days' fiddling, as the Cruise is not an instrument that's all that easy on the unwary beginner, due largely to the eccentricities outlined above. However, the clock diagrams above the mono and poly sections assist to some degree, and I assume reasonably helpful users' manual exists - there was none supplied with the review sample.

If you do get a chance to play the Cruise, don't let first impressions put you off; it's a much more complex and rewarding instrument than it appears.

The Siel Cruise has an RRP of £469 including VAT and is distributed in the UK by SIEL (UK) Ltd, (Contact Details).