JW Penfold
Bernard Babani Books
£2.95

A timely book on a trendy subject, MIDI Projects is a practical book principally concerned with interfacing synthesisers to your computer.

In addition to this the book considers the development of MIDI and fills in a lot of background knowledge which confuses newcomers to this recent development in the musical world.

MIDI stands for Musical Instrument Digital Interface. A MIDI allows you to program an instrument to play by itself controlled by the computer.

The book shows how to construct and modify an all-purpose interface for a wide range of computers including the Spectrum, QL and humble ZX81. The circuit is built around a general purpose 6402 UART chip (Universal Asynchronous Transmitter/Receiver). The text is detailed but gives no comfort to non-technical people. This is acceptable because the area of computer interfacing of any type should not be tackled unless you understand a little about what you're attempting to do. Blowing your computer via the expansion port is a short cut to an expensive repair bill.

The final section of the book dabbles in the circuitry required to drive any instruments based on the MIDI'S predecessor, the CV system.

For a home constructor bent on saving a few quid this book well worth a browse. The only qualms that I have is that of software compatibility. What good is an interface link without anything to drive it?

Penfold's style is easy to follow and the book is well worth considering especially at the price.

MACHISMO AND THE ART OF ZED80

If you were born with a soldering bit in your teeth and spoon-fed with flux, then RA Penfold has written just the books for you. Computer Music Projects and MIDI Projects are two short but densely-packed books full of techno-speak regarding the construction of add-ons for the Spectrum, amongst others, that will turn your computer corner into a mass of hi-tech spaghetti inside a week.

The music projects book is roughly in three sections. One deals with older synthesizers and how to build interface devices that use the control voltage in/output of the synth as a controlling device. The second section gives a series of projects that build up to form the component parts of an electronic (analogue) drum kit , again micro controlled while the third gives ways of building your very own sampler and, albeit a bit crude, a digital synthesizer. There is a final chapter to this book all about MIDI the author obviously thought the better of this and, it became the first chapter in his next tome MIDI Projects.

This popular (well it is in two books!) chapter deals with the basic format and protocol of MIDI and its modes. A sad omission here is the lack of a complete breakdown of codes common to all MIDI instruments. The rest of the book deals with building a MIDI interface and how to interface MIDI instruments. All fascinating stuff, I hear you say.

As we all know, the big thing with all interfaces is the governing software, and here the inventive Mr Penfold is horribly thin on the ground. A novice could have the impression from reading this that all a MIDI program for real-time sequencing needed was about eight lines of program. Although the author does sort of explain what is needed, the coverage given is very, very simple as regards the programming.

I suspect that the fun is to be had getting around all the headaches that do-it-yourself electronics plus programming can give you. Both these books are published by Babani Books Ltd and cost £2.95 each. Interestingly enough, the Computer Music Projects book has a copyright of 1885 - so it is obviously a return to Victorian Values for these circuits.