Electronic Music Circuits

By Barry Klein
Price £12.70
Published by Prentice-Hall (Blacksburg Continuing Education Series)

There are still very few books available that deal specifically with the electronics and computing of electro-music. Hal Chamberlin's authoritative book is one of the most popular. Here is another that deserves the attention of the more technically-minded musicians. Written by Barry Klein, an American engineering technician, it covers a wide range of synthesiser components based refund ICs, including dedicated music chips.

Starting with a chapter on synthesiser system design (strictly analogue circuitry), the various components that make up a synthesiser are discussed. Chapter two looks at power supplies, transformers, filter capacitors to IC regulators of various types. Chapter three covers control voltage generators and processors such as joysticks, pressure-sensitive and velocity sensitive keyboards. Circuits are provided for mono keyboard, single bus and duophonic three-bus, CV scaling, controllers (ribbon, pressure, joystick) as well as a 10-step sequencer, noise generators, LFOs, sample and hold, trigger extractor and an envelope follower.

Chapter 4 discusses VCOs, particularly exponential converters, current controlled oscillators, wave shaping and SSM, CEM circuit applications.

Chapter 5 on Filters explains active types, with several Curtis and SSM circuit examples from various magazine and manufacturers notes, concluding with brief mention of graphic EQs and vocoders.

In Chapter 6 analogue multipliers for VCAs and four-quadrant multipliers useful for signal modulation leads to miscellaneous circuits in Chapter 7. Delay lines, companders, BBDs, a simple mixer, and timbre modulator are detailed.

Finally, chapter 8 outlines a modular approach to building your own system from the circuits in the book, more towards monophonic than polyphonic, and there are some useful construction tips as well as IC information sheets.

The book is well written and the reader needs only a minimal knowledge of mathematics. Although components and their value are all given on clear diagrams, you'll have to be able to sort out track layouts for yourself since none are supplied. Most chips are available through selected suppliers in the UK.

Other books received:

The ZX Spectrum

By Ian McLean,
Simon Rushbrook Williams,
Peter Williams Price £5.95
Published by Prentice-Hall

A useful book aimed at the beginner who wishes to develop his computing talents. The straightforward text is well written, punctuated by cartoons and over 170 helpful diagrams and shows how you can make better use of the Spectrum's sound, graphics and data handling functions.

Chapter 8 deals with sound and shows you how to take a piece of music, break it into sections and convert it into a program to play a simple melody using the Spectrum's Beep parameters. Chapter 9 is pretty comprehensive dealing with user-defined graphics. The final chapter takes a quick look at how you can interface your Spectrum to the outside world via peripheral devices. All in all, a handy book that complements Sinclair's own manual very well.

ZX Spectrum User's Handbook

By RJ Simpson & TJ Terrell
Price £6.95
Published by Butterworth Group (Newnes Technical Books)

An important book for Spectrum users who wish to know more about the technical aspects of their machine. This book describes the features and operation of the Spectrum in great depth with detailed chapters covering data handling and colour graphics. A very useful section describes flowcharts and how they are best translated into working programs with step by step examples.

Both hardware and software are generously covered — ROM, RAM and the Z80A microprocessor as well as a comprehensive guide to machine code programming techniques with full listings of the machine code Instruction Set.

The chapter on sound is rather disappointing in comparison with other chapters, dealing mainly with the Beep function. A small section shows how you can create your own sequences and this really should have been expanded upon.

Even so, this is a good, technically-orientated book that deserves a place on the bookshelf of every Spectrum user who is serious about computing.

Prentice-Hall International can be contacted at (Contact Details).