This is not one but two sophisticated programs in one package. It's not possible to jump back and forth between the two, so you need to make the most of the first, 'The Sound', and to save the data you generate with it, before moving on to the second, 'The Player'.

'The Sound' is an attractive envelope generator program. It supplies sixteen preset envelope shapes and allows you to fiddle around with them or invent new ones. You fiddle using the function keys (a clear, detailed key strip is provided), the cursor keys and Copy. As you change various parameters, the new values are displayed numerically and an excellent four-colour graph shows just what's happening to your envelope shape. (For clarity, there are two graphs, one for the pitch parameters, another for amplitude.)

For anyone still struggling to understand exactly what the Beeb's fourteen envelope parameters actually do, this program gives as clear an idea as anything I've seen, for not only are the envelope shapes displayed graphically, you can play the note you've created using your Beeb as a sort of synthesiser keyboard: white notes on the keys from CAPS LOCK to RETURN, black notes between TAB and £. It's polyphonic, too, using all three tone generators to enable you to play chords and another row of keys (Z to ,) for noises from channel 0.

The menu allows you to store your new envelope in any one of the remaining fifteen locations, to summon up one of the others, to save envelops you've created on tape or disc, to load new ones, and finally to jump to the second program, 'The Player'. But don't jump until you're ready. It's impossible to get back into 'The Sound' without reloading from the beginning - which is particularly tedious when using cassette.

Once you've set yourself up with sixteen delightful envelopes (and yours couldn't be any worse than the sixteen supplied with the software), you're ready to make music with them. 'The Player' retains the synthesiser keyboard effect, but this time as you play notes, they appear displayed on two musical staves (treble and bass clefs), romping across the screen from right to left. The speed at which they travel is adjustable, and you can play with or without a metronome ticking out the tempo.

You can still play polyphonic chords and choose between the sixteen envelopes you have on board. In fact, you can use two at the same time by 'splitting' the keyboard at the note of your choice - for example, anything you play above middle C is envelope 12. The bottom row of keys still operate channel 0, so various percussive effects can be thrown in for good measure.

It's not easy to play satisfactory music 'live' (qwerty keyboards weren't designed for that), but it's only a short step from playing music to 'recording' it with the Sequencer. This allows you to store tunes of considerable length (up to 1024 beats of the metronome), one channel at a time, then to record another 'track' as the first one plays back, then another on top of that - plus a percussion track on channel 0 if you wish. If you make a mistake, individual notes on individual channels can be deleted, inserted, or altered for pitch or duration. Finally, when you've created a 1024-beat, four-voice masterpiece, you can save the whole sequence on tape or disc.

If that sounds like a lot of complicated operations, it is. But writing polyphonic music is a complicated operation however you do it and the Beeb's sound facilities wouldn't be so interesting if they weren't so complex. Of all the current software designed to 'reord' three or four-channel music on the BBC Micro, this program is perhaps aimed particularly at the musician. Not only do you enter your notes by 'playing' the keyboard, rather than digitally, you also see something like the written melody on the screen, which helps if you're familiar with written music.

Congratulations to the author, Geraint Wiggins, for two clever and practical programs, a clear and informative instruction booklet - and a quite brilliant example piece for the Sequencer, to demonstrate just what is possible.