The Music 500 is Acorn's latest add-on for the BBC micro and possibly the most unusual. Launched at the Compec show in November last year the Music 500 is a programmable high quality music synthesizer.

Designed by Hybrid Technology Ltd, and marketed by Acorn, the Music 500 is the size of a single disc drive and has its own on-board power supply with mains switch located at the rear of the unit. It is connected to the BBC micro via a 34-way ribbon cable to the 1MHz bus. The Music 500 unit is designed to be connected directly to a stereo amplifier via a standard 5 pin DIN socket. The front panel of this synthesizer differs from most others in as much as there are no knobs to twiddle, and no music keyboard either.

The Music 500 relies upon the Beeb for all of its commands which have to be pre-programmed using its own language called Ample. The audio output is very good quality. The sounds are clear and crisp - a feature the Clef system could do well to emulate. Listening to some of the demonstration programs included on the cassette provided certainly indicates that the unit is capable of very varied sounds. Incidentally there is a tape to disc transfer program included which allows you to transfer all of the cassette's contents to disc if you wish.

There are a total of sixteen oscillators in the Music 500 each programmable in a similar way to those in the Clef system. Initially they are set up in pairs giving eight separate voices. However, different configurations are possible such as one incredibly rich voice using all sixteen channels - something the Clef can't manage. The channels in a voice can be offset in pitch from each other, they can modulate one another using ring, frequency, or synchronization modulation to allow very complex sounds to be created. Each channel can be directed to one of seven stereo positions to add even more depth to the sound.

There are 13 programmable, and initially preset, waveforms for instant use along with 13 programmable preset envelopes. These can all be redesigned to your own specification. As well as taking preset designs, the waveforms and envelopes can be set up 'on the fly' while music is playing to give an effectively infinite variety. Waveforms are designed either in terms of harmonic content or 'graphically'. This latter method can be used along with the random function to produce pseudo noise for percussion effects. Envelopes can also be defined in two ways. Either a normal ADSR construction can be used or alternatively a more complex multi-segment construction of your own can be initiated.

The User Guide that comes with the Music 500 is rather disappointing. The glossy cover hides pages printed with a dot matrix printer. It would seem that it was put together in somewhat of a hurry as it has some odd page numbers while others are blank.

The guide is split into a tutorial and a reference section. The tutorial part is very poor. It covers little ground in a most confusing manner. However, the reference section contains a dictionary of Ample words and that is where a many of the joys of Ample are to be found hidden.

Ample is a word based language. That is, 'programs' are user defined words that call up other user defined or predefined words. Any word can be called up into a text buffer and edited in the same way as a Basic program is edited using the cursor, Delete, and Copy keys. Advocates of Logo will recognise this programming method. In this way a typical music program might be a single word ('play' in the demos) which calls up first a series of sound set up words and then further words that comprise the actual score. This hierarchical structure allows you to deal with a complex programming task a piece at a time.

Scoring in Ample is a simple matter of naming notes. If the note is to rise in pitch over the preceding note a capital letter is used. If the tune descends, a lower case letter is used, though an octave number can be defined for each note if you prefer. In addition, the note length and starting pitches are defined numerically and bar lines can be added. Ample will, if asked, check your composition for the correct number of beats to the bar as it plays it.

The most powerful aspect of Ample is its multi-tasking ability. Separate 'players' can be scored individually and then all set playing together, in time. You can share one player's task from the keyboard, as he is playing, and change his instrument with a few deft stokes of Ample so that, say, a couple of foot is cut off his bassoon (or whatever). This means that you can experiment with the sound of an instrument 'in situ', in the middle of a piece.

Ample doesn't stop there either. The predefined words are all definable too. So that you could, for example, redefine the 'bar' word to stress the first note in every bar. The entire language is amazingly complex and versatile. It makes the software efforts of the Clef system look particularly lame.

Whilst it does take time to get used to the alien nature (at least to most Beeb users) of Ample, it is relatively easy to start producing simple music using only a smattering of the commands available. I managed my first composition (a hymn) using four part harmony in under a week.

You don't have to be a musician to appreciate the Music 500. Indeed Ample is a more than a little daunting to those not experienced in programming. However, a reasonable knowledge of music and some idea of the nature of sound is essential to make the most of this device. For the struggling artist with no liking for the computer, Acorn is soon to bring out a keyboard to complement the Music 500 and some very impressive software is promised too.

Meanwhile there is quite enough to get to grips with in the Music 500 package. For £199 it is difficult to imagine a more comprehensive musical add-on for the BBC micro.

If you are desperate for a keyboard, software is available from ATPL to interface its Symphony to Ample. This will cost you about £15 on top of the £125 for the Symphony keyboard. The software is in the form of a keyboard driver and a demo program. The demo is fairly limited. It offers only preset sounds from the keyboard and some pretty horrendous rhythm tracks. However the demo is only that - a demo. What you do with the interfacing software is really up to your imagination and your skill using Ample as a programming language. When you become proficient at using Ample and decide that you really want to play the Music 500, Symphony and Ample together provide a good vent for your creative urges.

Product: Music 500
Supplier: Acorn Computers Ltd. Fulborn Rd., Cherry Hinton, Cambridge, CB1 4JN. 0223-245 200
Price: £199