AT LAST, HYBRID Technology have released the Music 4000, the keyboard for their Music 5000 synth. It's a four-octave full-size keyboard, with a footswitch and a 38-page manual. There's also a 40/80-track disk containing the installation program, M5000 menus and modules, six demo music tracks, two sound libraries, two mixes for keyboard composition, the M4000 module, keyboard effects and a real-time recorder.

The keyboard plugs into the Beeb's user port and needs a complete M5000 system. But the M4000 is more than just an add-on that plays the M5000's sounds; it is a versatile composing tool with two more friendly front ends for AMPLE.

The Beeb can now become a "multitrack digital real-time recorder". Play the parts of a piece separately in real time on the keyboard, record them on the AMPLE Recorder, then replay them together. The M4/5000 has a maximum of eight tracks, providing only one note at a time is recorded per track.

Real-time input on the M4000 can be quantised to put your playing back on the beat, and in fact, quantisation works well with everything but the crudest technique. The quantum interval can be adjusted to give the desired fine tuning, useful both for different qualities of technique and for "character" in pieces.

Tempo can also be set for recording and playback. Record like Rolf Harris on stylophone and play back like Keith Emerson on something illegal. Recording can be carried out with any available instrument, but instrument and tempo information is not saved with the recording. These have to be added at the mix stage, either before or after recording.

You can also use the M4000 as a step-time sequencer. Keypresses can be sent to the Staff or Notepad editor as input to an AMPLE word. One keypress is one note, with note length assigned by repeated presses of the footswitch, and rests by footswitch without keypress.

However, all other step-time information must be input from the computer keyboard. There seems little point in a music keyboard when most of the adjustments for input need to be made from the computer, so if your only interest is in step-time programming, give the M4000 a miss.

The M4000 is also a performance keyboard, though. Hybrid seem a little ambivalent about this, preferring to play up the composing side. So they call it a "composing tool", yet provide (some) facilities that ensure you can perform with it if you want to. You can play live over a mix, use the keyboard like any other stand-alone synth, or program individual sounds on separate keys to use it as, say, a digital drum kit.

However, the keyboard has only one performance control: the footswitch. There's no pitch or mod wheel, no control for portamento or vibrato, no touch sensitivity, no keyboard splitting. Presumably, the computer keyboard or a joystick could be made to carry some performance information, but Hybrid don't tell you how to do it.

The lack of performance features is a shame, because the M4000 comes with a library of another 71 excellent sounds. Although some are very similar to each other and others are only gimmicks, most are impressive, and include massive stacking of 16 voices onto one note.

There are also some effects, achieved by assigning AMPLE's eight available players to a single keypress. Thus a simple sound can be given eight echoes, or can be used in an arpeggio of up to eight notes. Notes can also be stacked into a chord for transposing across the keyboard, while a keyboard panel allows you to pan the voices, assigning the stereo position of the first and the offset for the rest - so an echo can be reflected alternately left and right or an arpeggio might fling its notes randomly around the sound space.

The Music 4000 is a slightly uneasy compromise between performance and composition. It does, however, succeed in making the M5000 into a mature, versatile setup. It's definitely a worthwhile buy for current M5000 owners, and it makes the whole system more attractive to musos who want tunes first, technology second.

Price Music 4000, £169; Music 5000, £161; both prices including VAT and p&p

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