In writing the book, we recognise that readers will have a variety of backgrounds, interests and points of view. Some will be particularly interested in audio engineering topics and will wish to get down to the ‘signal processing’ as quickly as possible. Others will come from a musical background, and may prefer a more gentle introduction, emphasising the musical context. Yet others may approach the subject from an interest in music technology, and would prefer a way into the subject from a systems-oriented perspective. We have therefore organised the text into several essentially free standing parts, which can be read in various orders to suit the particular needs of the reader.

The book is split into six parts that can be consistently read from start to finish (although this is by no means the ideal route for every reader). Part 1 introduces the reader to the ways in which sound generation and processing technology has developed and has influenced the artistic world throughout the twentieth century. Once the reader understands the context for the technological manipulation of sound, we can begin to explain the theory of sound transmission and storage. Therefore in Part 2 we introduce the signal processing techniques that form the basis for understanding how sound can be digitally recorded, altered and played back. Equipped with these theoretical tools, we look in Part 3 at the structure of contemporary music technology systems - considering their interconnection, basic functionality and use of signal generation and processing techniques. The reader is then acquainted in Part 4 with the fundamentals of digital computer systems so that he/she will understand the digital ‘engines’ that are inside every synthesis or processing system. In Part 5 we justify the need for learning to program these systems, and give tutorial guides on programming for MIDI, digital audio and multiple media. Finally Part 6 considers the design of the control interface to digital instruments, and involves the reader in thinking about designing the instruments of the future.

Chapter Structure 

This introductory section describes the technological and artistic context within which the evolution of electronic sound and instruments have developed. Few if any human endeavours develop in isolation from related ideas, and this is as true for audio technology as for anything else. Chapter 1 briefly sets out the historical context of developments in sound generation and recording, composition and performance, which have provided the motivation for the systems described in the book.

Chapter 2 describes the nature of the acoustic signal which is manipulated within digital audio and computer music systems. Chapter 3 then considers the way in which the signal is represented and processed in elementary signal processing algorithms. In essence, this section provides an introduction to signal processing for digital sound systems.

This section deals with the structure of contemporary music technology systems, set within the context of the way in which people have used such systems over the years. The MIDI specification is introduced and discussed in chapter 4. This leads to a description of the essential functional components of modern music technology systems in chapter 5. It concludes with an in-depth discussion on how signal processing techniques are used within such systems.

This section describes the computer systems which are used to realise the sound processing techniques described in parts 2 and 3. It serves as an introduction to computer fundamentals for those who have not studied computers before, and who wish to understand the way in which they are used in music synthesis systems. These chapters concentrate on the issues common to all conventional processors, and do not focus on any one specific device, so that the material will remain relevant as the technology changes. Chapter 6 introduces the elementary logic gates that are fundamental to computer operations. Chapter 7 considers the structure of a typical computer system - its hardware and software. Chapter 8 then describes how the computer interacts with the outside world by considering the topic of computer interfacing.

The processes of writing computer programs for audio, musical and multiple media purposes are introduced in this section. It is quite feasible for the enthusiast to do this, so that he or she can contribute to the development of the subject in terms of technique and music, provided that a suitable introduction to programming is given. This is the purpose of chapter 9 and examples are based on algorithmic composition for MIDI systems. Chapter 10 extends the programming techniques covered in chapter 9 to show how sound can be synthesised and processed using the unit generator concept. The real-time control of signal processing and multiple-media applications is introduced. Examples of direct sound synthesis and manipulation are given using the MIDAS system as a framework.

It was stated above that one of the objectives of this book is to assist the committed enthusiast (lay and professional) to contribute to the development of music technology and audio processing systems of the future. This section deals with the way in which people interact with such systems and considers a ‘human factors’ approach to their design. It concludes with a case study which describes an outline design of a new audio-visual instrument that the reader can take on and develop further.

As stated above, the material is arranged so that the six parts of the text can be read largely independently of each other. This means that readers can choose from several flow lines through the book.

Those interested primarily in sound processing and audio engineering might read the parts in the following order: