Digital Sound Processing for Music and Multimedia

Ross Kirk, Andy Hunt

• Publisher: Routledge
• Year: 2013
• ISBN:
  9781136116377
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Acoustical Engineering
• Index: Technology & Engineering

Provides an introduction to the nature, synthesis and transformation of sound which forms the basis of digital sound processing for music and multimedia. Background information in computer techniques is included so that you can write computer algorithms to realise new processes central to your own musical and sound processing ideas. Finally, material is inlcuded to explain the way in which people contribute to the development of new kinds of performance and composition systems. Key features of the book include:
· Contents structured into free-standing parts for easy navigation
· `Flow lines' to suggest alternative paths through the book, depending on the primary interest of the reader.
· Practical examples are contained on a supporting website. Digital Sound Processing can be used by anyone, whether from an audio engineering, musical or music technology perspective. Digital sound processing in its various spheres - music technology, studio systems and multimedia - are witnessing the dawning of a new age. The opportunities for involvement in the expansion and development of sound transformation, musical performance and composition are unprecedented. The supporting website (www.york.ac.uk/inst/mustech/dspmm.htm) contains working examples of computer techniques, music synthesis and sound processing.

Part 1

Context

This introductory section describes the technological and artistic context within which the evolution of electronic sounds 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.

There is little assumed knowledge on behalf of the reader, other than an interest in sound and music, and a desire to understand the way that its technology has developed along with the artistic practices that produce it.

1 Sound generation and recording in the twentieth century

Overview

The aim of this chapter is to introduce you to the art and techniques of electronic sound creation and storage in the twentieth century and thus to encourage you to think about how these trends may develop into the next century.

This chapter is concerned with the ways in which computers and electronic systems have been used in the production and processing of sound, and examines the effect this has had on engineers, musicians and computer users. It sets the scene for later chapters by showing that during the entire history of recorded sound, the art of the recording engineer and of the musician have been inextricably intertwined — developments in the one encouraging further experimentation in the other.

The material in this book is dedicated to the furtherance of this exchange. It is therefore appropriate to review the historical context of this mutual development in this opening chapter.

Topics covered

• History of interfaces in electronic sound generation.

• Musical changes and trends in the early twentieth century.

• Early electronic instruments.

• Electronic music studios.

• How sound recording has affected music.

• Synthesisers and the live performance of electronic music.

• Digital sound and its processing and control.

• Digital computer music systems.

1.1 Setting the context

In this age of rapid technological development it is important to keep a sensible perspective by reminding ourselves that music has been a fundamental part of every human society for thousands of years. By contrast computers have only been available to the general public since the 1980s.

However, the seemingly independent disciplines of music and computing appear to be increasingly interwoven in the modern western world. The technological advances of the latter half of the twentieth century have allowed large proportions of the population to have access to music and computing facilities as an integral part of everyday life. The two subject areas are inextricably linked now that digital technology has become the prime method of storing music and an increasingly important way of producing it.

It is the purpose of this chapter to step back from the relentless pursuit of technological advancement for its own sake, and to examine the ways in which humans interact with computers when involved in musical activities. By examining some of the ways in which people perform with traditional musical instruments (methods which have developed throughout history) we can gain valuable insight into the design of interactive computer interfaces, the study of which is still, by comparison, in its infancy.

1.2 The effect of technology on sound production

The generation of sound waves requires physical vibration. As human beings we are equipped with versatile vocal systems which provide us with our most direct way of producing sound; a new-born baby wastes no time in demonstrating this! However, throughout history, we have felt the need to use tools to create external sounds. The manufacture of such tools (or ‘instruments’) demands technical knowledge and technical development.

When each new technical innovation is used to make music it influences the range and style of music produced. For example, in the early 1700s Bartolomeo Cristofori invented a harpsichord with notes that could be played soft or loud (‘gravicembalo col piano e forte’). Composers responded by writing keyboard music with expressive touch and volume.

Sometimes the reverse is true: the development of artistic thinking can set the goals for the instrument designers. At various points in musical history musicians have attempted to extend their musical language. This has often required new types of musical instrument. The twentieth century has seen an explosion of music making all over the world, and the technology of the twentieth century has been regularly called upon to produce instruments capable of new forms of expression.

Traditionally, acoustic instruments are played by one or more of the following techniques: plucking, strumming, bowing, hitting, blowing, keying or stopping (placing fingers over holes or on strings). In all of these techniques, the performer's physical action causes vibrations in the instrument, thus producing sound. The musician is therefore continuously in touch with the instrument as it is played. Once electricity is introduced into the range of technological tools available for making music, this situation is extended since it is possible to produce electric instruments which can be played without direct physical contact.

It is with the above points in mind that we now examine the history of the development of music and recording technology from the point where an electronic circuit was first used to make a musical instrument. Special emphasis is given to the ways in which musicians have been expected to interact with the technology as it develops.

1.3 Musical changes from 1900–1950

In this section we set the scene for the development of twentieth century music technology by considering how music itself was undergoing great changes in the early 1900s. It is important for engineers and musicians to appreciate the background to their disciplines since it is then easier to place new developments in context.

The early part of the twentieth century saw music in the western world undergoing huge changes. Symphonic works had grown to enormous lengths and involved hundreds of performers singing and playing with complex harmony in the so-called ‘Romantic’ period.

1.3.1 ‘The death of music’

The Romantic composers seemed to be running out of steam. Everything had become so large, so grand and complex that there was a feeling that everything that could be composed had already been composed. In other words there was a concern that if you pushed music any further it would just fall apart.

Austria's Gustav Mahler (1860–1911) is often acknowledged as the founder of modern music, but he saw himself as encountering ‘the end of music as we know it’. His music evokes a sadness of times lost for ever. Other composers such as Jean Sibelius (1865–1957) stopped composing their traditionally romantic and nationalistic works at the turn of the century and felt compelled to write in a more abstract style.

It is interesting to note that in the field of technology there was a similar feeling of despair at the arrival of the twentieth century. Bill Gates (in his book The Road Ahead) mentions the US commissioner of patents who asked that his office be abolished in 1899 because ‘everything that can be invented has been invented’.

1.3.2 ‘The re-birth of music’

Other composers saw the incoming century as a challenge to completely rethink their music. For the purposes of discussion we will classify the new music as exhibiting one or more of the following characteristics:

• impressionism (new harmonies and textures)

• rhythmic violence (complex and energetic rhythms)

• atonality (the absence of traditional harmony)

• timbral manipulation (the production of new types of sound)

Each of these characteristics is now discussed.

1.3.3 Impressionism

One of the leading composers in Paris at the end of the nineteenth century was Claude Debussy (1862–1918). Debussy's music inherited the rich harmony from Romanticism but mixed it with a new emphasis on musical ‘texture’. No longer was it important to have the ‘biggest and best tune’, but rather to develop washes of sound and threads of melodies. This was termed ‘Impressionism’ — a phrase that was already in use to describe the many paintings which used washes of colour and paint texture to describe impressions of a scene (rather than a photographic representation).

It is perhaps relevant to note that the technological invention of the camera had forced painters to change their art. Artists were no longer able to match the camera's ‘perfect’ reproduction of a scene and thus they moved towards more abstract and representational views (which the camera could not compete with). Other composers also regarded as impressionists include Maurice Ravel (1875–1937) and Frederick Delius (1862–1934).

1.3.4 Rhythmic violence

Other composers took a different route. Rather than creating gentle textures and ‘washes’ of sound, these composers re-established the use of striking rhythms — particularly by using complex time signatures with unusual accents.

Igor Stravinsky (1882–1971) underwent a large compositional shift from his 1910 ballet The Firebird (which drew on the rich tradition of Romantic music) to his 1913 ballet The Rite of Spring. The premiere of this work in Paris caused a riot, as people were shocked not only by the subject matter and the appearance of the dancers, but also by the music. Chords made up of two different keys (bitonal) were thumped out in a vicious rhythm, and many passages were atonal (see Section 1.3.5). It is difficult to listen to this piece today with the same shock and horror which the Paris audience experienced (although it is worth noting that this style is often used in film music — notably John Williams' score for Jaws).

Other composers noted for their highly rhythmic music include Bela Bartok (1881–1945) and Serge Prokofiev (1891–1953).

1.3.5 Atonality

While many of the Romantic composers were worrying that they could not stretch musical harmony any further without totally destroying the key relationships (fundamental to music since people could remember), others were exploring a new form of music which had no central tonal base whatsoever.

Arnold Schoenberg (1874–1951) composed many works which could be described as being Romantic in style. However, he felt a growing conviction that music had to change in order to remain relevant and to have any future. He took it upon ...