There is a tendency in many books on computer programming to skip over the sound capabilities with a brief nod to sirens and Space Invader bleeps. This is understandable: almost anyone can get to grips with graphics and produce pretty colours and shapes on the screen, but sound and music are much less intuitive, and the commands built into the Amstrad offer an almost infinite variety of possibilities.

Besides, if you want to score a tune in three-part harmony you have to know music pretty thoroughly as well as how to program with the sound commands. Jeremy Vine's book has been written to fill this gap. It deals with sound on the CPC464, with no digressions.

Chapter 1 starts with the sort of fundamentals you're going to need to deal with sounds effectively: the meaning of amplitude, pitch and duration, and the three channels on the sound chip. The next chapter introduces the SOUND command, which can take a large number of parameters - the author begins with just two, the compulsory ones. Then each of the optional parameters is explained, bringing in the associated BASIC commands such as S Q Next the concepts involved in music are dealt with, such as the stave and musical notation, which you will need if you want to transpose scores into the Amstrad (always remembering copyright, of course!).

Finally (in the music section) the volume and tone envelopes are discussed. Now comes the bit that all real programmers and interested in-the sound effects! Starting with a half-dozen throw away effects programs, the author goes on to provide a program that lets you generate different envelopes and test their effects, and touches on percussion (1). This is followed by an amazingly simple synthesiser program that you play from the keyboard. The book ends on a slightly disappointing note - no pun intended - with the usual obligatory copying of the CPC 464 command list which you've already got in the User Guide, but given the rest of the book, I think the author can be forgiven. The style is light-hearted and easy to read, and though the price-per-page is a little bit high, this is a useful book for your collection.