Casio's CZ synths offer quite amazing value for money, and it's hard to see why the opposition aren't as worried about them as they ought to be. The 5000 is the third in the series, father to the CZ-1000 and grandfather to the compact and powerful CZ-101. In fact the two earlier models have almost identical specifications (the difference lying in the size of the keyboard) but the new 5000 does include several changes and improvements.

All the synths, of course, work on the Phase Distortion principle, which does a quick fence-straddling job between analogue synthesis and Yamaha's FM system. The result is that all three synths can produce the smooth analogue sounds of the Juno 106 or Korg Poly 61, together with the sharpest FM effects of the Yamaha DX7. And, because the 5000 has a powerful built-in sequencer, a lot of the effects of the Yamaha CX5 music computer as well — but that's another story.

All this, and the 5000 also offers a full-scale five-octave keyboard (surprisingly without velocity sensitivity) which makes it very much a full-spec professional synth. The end of the portable Casio then — the 5000 masses about the same as a Juno 60 and is notably lacking in built-in amplifier and speakers or battery power.

There's a stereo chorus and an expanded memory which allows for 32 factory sounds (which are named on the DX7-style LCD display) and 32 user-programmable memories (which are given bank and patch numbers on the same display). The socket for loading factory or user-programmed sounds from ROM or RAM cartridges is transferred to the rear panel, where it's pretty hard to reach should you want to use more than one cartridge in a set.

There are only a couple of changes to the actual voicing of the synth though, and it's fair to point out that the main one is simply the provision of a stereo chorus. The basic CZ design allows you to produce twangy filter-like sounds despite the fact that the synths don't actually have filters, but the chorus improves swooshy string sounds and the like. The 5000 is also 16-note polyphonic, but there's still an oddity in the note assignment which means that playing all the available voices with one hand will kill any notes held with the other hand even if the sound is a fully sustained organ-type effect.

As before, the synth produces eight digital waveforms ranging from the basic sawtooth and square to unusual sine/square shapes and complex noise forms. You don't need a filter because you can use an eight stage envelope to sweep through the waveform table — shades of the PPG system — and so produce smooth or sharp changes of tone. Apart from an envelope for the waveforms there's another for the DCAs (digitally controlled amps) and for the pitch of the oscillators. You can bank the oscillators, giving the possibility of detuning or interval effects but halving your polyphony, and there's also a keyboard mode referred to as Tone Mix which allows you to play two different sounds simultaneously, again halving the polyphony.

All the sound parameters are adjusted using a pair of Value Up, Down controls adjacent to the LCD display, except the Envelope Stage being edited which has its own Up/Down controls (which seems a little unnecessary). Usually the display offers more than one parameter to edit — for instance Envelope Step, Rate and Depth — and you select which parameter you're altering with a pair of cursor keys.

Of course the 5000 comes with a variety of imitative sounds — brass, strings, xylophone, bass and so on, but you can go really mad with your own sounds with bizarre digital effects, glides, sliding chords and much more. Effects include a Ring Modulator and Noise Generator which can be selected in various combinations and which help to produce metallic sounds or the usual helicopter and surf cliches. Editing can be slow (particularly on the eight-stage envelopes) but that's the price to be paid for the CZ synth's great versatility. As for performance controls, there's polyphonic Portamento as well as Glide, each with an On/Off switch and time parameters; Bend Range and Modulation Depth for the performance wheels (the pitch bend wheel being sprung and the modulation wheel having an On/Off switch); an Initialize setting for simplifying sounds before building new ones; and a depth control for the chorus, which isn't programmable.

Also there's MasterTune (digital rather than a simple knob), Key Transpose (for those who can play in fewer keys than they ought) and Solo mode, which doesn't stack up the oscillators to play in unison but which is nevertheless helpful if you select some of the 5000's screamier leadline sounds.

As mentioned, the Tone Mix keyboard mode allows you to layer two sounds, but the 5000 also introduces a Key Split mode which allows you to play two sounds either side of a split point programmable from Key 1 to Key 60. This is handy because it allows you to put, perhaps, a single special effect sound on just the top or bottom key, although you're more likely to use the bottom octave for a bass sound under strings or the top two octaves for a lead sound over brass, for instance.

The sequencer is pretty powerful but a little reduced in pointfullness by the fact that the 5000 only has a pair of stereo outputs. The sequencer has eight tracks which can play back individually or simultaneously with up to eight different sounds, which implies that the 5000 can work in the powerful MIDI Mono Mode as we'll see. But since you can't equalise or treat the sounds individually it would be difficult to regard the sequencer as a complete compositional system — compare the SCI SixTrax and Max which are similarly lacking.

The sequencer's Rev/Fwd/Play/Stop controls act like a tape recorder and even allow you to scan backwards through a sequence. Record, Reset (to the start of a pattern), Real Time and Manual (more often referred to as Step Time) are self-explanatory, and the eight sequence buttons double as note length selectors for step time programming. There's a Track Check button which lights an LED above any sequence which has already been recorded, Tempo Up/Down controls and a Repeat button for looping sequences.

'Multitracking' on the 5000's sequencer is fast and easy, and if you've used all the available voices the synth just stops responding to the Record control. Realtime recording allows you to specify the number of voices recorded in each pass, the tempo and the time signature using the Value Up/Down buttons, and Record/Play produces a bleeping metronome with an accented downbeat. When you're finished, select a new sound, erase another sequence, go into Record, play any existing sequences and record along with them. Simple.

Step Time offers Beat Length, Rest, Tie, Triplet, Repeat and End options and you can simultaneously play any combination of step time and realtime recorded sequences. Alternatively you can play the 5000 from an external sequencer or keyboard via MIDI, selecting any receive channel in Poly mode and any six channels for monophonic response with different sounds in Mono Mode. Program changes from external sources can be accepted if desired.

Sticking our heads around the back of the 5000 and into various nooks and crannies previously undiscussed, we can find an Edit/Compare function for checking progress during sound creation, facilities for dumping sounds to tape, stereo outputs, a headphone socket, volume pedal and sustain footswitch sockets, a memory protect switch and MIDI sockets (just In and Out; perhaps Thru as well on production models).

The only bad points about the 5000 are the styling, with the main control buttons being particularly clumpy and old-fashioned (maybe these will be replaced by something a little more modern); the weight, which seems unnecessarily great; and the lack of multiple audio outputs.

Apart from those minor points the thing's astonishingly good value for money. No longer will you have to choose between the smooth sounds of analogue synthesis and the clinical precision of FM — the Casios can do (some of) the best of both and a good few sounds denied to either. With Tone Mix or Key Split you can have two sounds at once, with Solo mode you can have fluid leadlines, with the sequencer you can have long and complex compositions with up to eight different sounds playing simultaneously.

Fully professional, the CZ-5000 is by far the best synth you can buy for the money on the market today.

For: The sounds; split, layer and sequencing facilities; price
Against: Styling; weight; limited audio outputs

CASIO CZ-5000 - RRP: £955