WHAT'S THIS? An electronic keyboard with two keyboards? What on Earth for? Well, I suppose most people do have two hands, so they might as well have a keyboard each, instead of having to make do with sharing one.

Actually, the real reasoning behind the Casio DM100 having two "manuals", as they say in the business, is probably that the designers want to encourage people to take up organ (or, in today's parlance, "multi-keyboard") technique, which is distinctly different from say, synthesizer or piano playing. This is a budget instrument, aimed fairly and squarely at beginners. When the people who buy it stop being beginners, the chances are they'll want to progress onto a fully-fledged multi-keyboard, complete with pedals, flashing lights and sunroof. For the first-time driver, how well does the DM100 perform?

Just for a laugh, let's turn on the demo. It demonstrates the machine's capabilities well enough, but this is the third Casio keyboard I've looked at recently that's featured the same demo tune. (It's one of those tunes that go around in your head for hours and take you to the verge of madness and back.)

But down to business. There are 28 sounds in all, discounting the rhythm section. Eight of these can be played from the upper keyboard, 20 from the lower. For this price, nobody can expect top synthesizer-quality presets, and needless to say, nobody gets them either. By and large, though, they do sound like their descriptions and are perfectly usable - whatever that means. The Piano suffers a little from "vibrato disease" (ie. it wobbles about a bit) but is otherwise fairly good, and the Chorus tends to slide annoyingly up to the note. A little stereo delay, available from the front panel, brings many of the sounds to life, and Casio have also gone to town on stereo panning for one or two presets. The Bells, for instance, sound first in the right speaker, then in the left, before wandering off into the distance like a lost cow. As on many portable keyboards, the pipe organ sound is particularly good. Usefully, the key marked Bass produces two bass sounds, either side of a fixed split point: one a string bass and the other a slapped bass.

On the whole, I preferred the lower keyboard's "PCM" sounds to the upper, which suffer far more from noise. The Harpsichord, for instance, exhibits a strange hiss, the Vibes brings out an odd chiming sound on the lowest fifth of the upper keyboard, and the Violin sounds like, well, an oboe.

The keyboards themselves are not touch-sensitive - it doesn't matter how hard you hit them, the sound remains at the same volume - but then that's not to be expected at this price. The upper keyboard has 32 keys (two-and-a-half octaves) and is four-note polyphonic, which means the greatest number of notes you can play at any time is four. The lower one has 49 keys (four octaves), and is ten-note polyphonic, so absolutely no problems there.

Before we finish talking about keyboard sounds, we come to an innocent-looking orange button lurking at the right-hand side of the control panel. Marked "210 Tone Bank", this lets the user choose from 210 different combinations of the 20 lower-keyboard sounds. Although this feature does not introduce any new sounds in itself, it adds hugely to the variety of sounds that can be created by combining them. It's very easy to use, and the only thing you need to worry about is that because two tones are combined, the keyboard is reduced to five-note polyphony.

The drum and percussion sounds are of reasonable quality. There are 42 in all, and some have unfortunately had "creativity" applied to them in the design lab which makes them sound a touch idiosyncratic. The Cymbals are a case in point: each of them has a panned shimmering effect that is (probably) meant to represent the difference in sound as the cymbal rocks back and forth after being hit. Somehow, it doesn't quite work. You can "tap" all the percussion sounds from the keyboard, though seeing as the DM100 doesn't have any kind of onboard sequencer, there's no way of storing any rhythm patterns you might come up with - unless you record them "live" onto tape.

If creating your own drum patterns doesn't interest you, the DM100 does incorporate its percussion sounds into 20 preset rhythms. These are well composed - not too busy, not too boring - but not, I would guess, as "modern" as most novice players would like. The same goes for the intros, endings and fill-ins which can be selected at any point, and for the usual auto-accompaniment features like "fingered chords", which are available in two modes: your choice depends on how lazy and/or incompetent you are.

The DM100's biggest surprise - aside from its pair of keyboards, of course - is that it also functions as a sampler. Through a built-in microphone, you can sample four different sounds and hold them in the machine's memory. Adding new sounds to your original four deletes the old ones automatically, and there's nothing to warn you that you're erasing sounds, so you have to be careful. Maximum sample time is 0.7 seconds for each of the four samples, though if you only want to sample two sounds, these can each be 1.4 seconds long.

You're not limited to using the internal microphone, since a line-in socket on the back panel enables you to connect a record deck, radio, CD player or whatever, and record directly from that. The resulting samples are of infinitely higher quality than anything you record with the mike. All your samples remain in memory when the unit is switched off: after a few minutes of inaction, the DM100 gets bored anyway and turns itself off, but at least when it wakes up it still remembers your samples.

The DM100 is unique. The mini-keys may be good for children to learn on, but they can be a little too fiddly for anyone used to the normal-sized article. But then the DM100 is an instrument designed for beginners, particularly those who are attracted to the multi-manual side of keyboard playing. It introduces the basic functions of electronic keyboards, such as auto-accompaniment, rhythm sections and sampling, without being overly complicated.

There's no point buying a Mercedes before you've passed your test. Try a Mini instead. Here's the keys...

CASIO DM100 KEYBOARD: £299 Inc VAT.

INFO: Casio Electronics Co, (Contact Details)