Musical Sound Effects

Analog and Digital Sound Processing

Jean-Michel Réveillac

• Publisher: Wiley-ISTE
• Year: 2017
• Print ISBN:
  9781786301314
• Edition: 1
• eBook ISBN:
  9781119482628
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

For decades performers, instrumentalists, composers, technicians and sound engineers continue to manipulate sound material. They are trying with more or less success to create, to innovate, improve, enhance, restore or modify the musical message. The sound of distorted guitar of Jimi Hendrix, Pierre Henry's concrete music, Pink Flyod's rock psychedelic, Kraftwerk 's electronic music, Daft Punk and rap T-Pain, have let emerge many effects: reverb, compression, distortion, auto-tune, filter, chorus, phasing, etc. The aim of this book is to introduce and explain these effects and sound treatments by addressing their theoretical and practical aspects.

1
Notes on the Theory of Sound

This chapter presents concepts that are indispensable to understanding and studying the phenomena associated with sound. In this study, readers can find the details required to discuss the variety of ways that exist to process sounds.

Mathematical equations are deliberately presented in their simplest and purest forms, without going into detail and avoiding any mathematical proofs. However, the standards of scientific rigor to which all physical sciences are committed have not been lost.

1.1. Basic concepts

We shall begin by describing the nature of a sound, followed by a few of its characteristics, before turning to the question of how our ears work. This leads into an analysis of the typology of sounds, spectral analysis and timbre.

To conclude, we will present the fundamental aspects of the propagation of sound, and we will consider a few common phenomena to be explored in more detail in subsequent chapters.

1.1.1. What is sound?

Although this question might seem simple, the answer is by no means easy. There are two ways to approach this topic: from a purely scientific perspective, working from the laws of physics, or alternatively by thinking about how our senses allow us to perceive sound.

Physicists view sound as a mechanical wave that propagates as a perturbation within an elastic medium or object. In other words, they view sound as the forward-and-backward motion (mechanical oscillation) of particles around their resting position. Electromagnetic waves, on the other hand, propagate as energy in the form of an electric field coupled to a magnetic field.

Figure 1.1. A simple example of a mechanical wave. Here, the wave is created on the surface of the water after a stone is thrown in

Many people will find it easier to define sounds as auditory sensations.

Sounds are produced by vibrating objects. These objects are sources, and the environment in which the sound is emitted carries the sound to our ears. When a sound reaches our ears, our brains allow us to perceive it, become aware of it and interpret it.

Most of the objects around us can produce sounds when they interact with shocks, friction, airflows or deformations. Who has not entertained themselves by twanging a plastic ruler at the edge of a table?

Figure 1.2. Vibrating ruler at the edge of a table

Sound cannot propagate in a vacuum, since there is no medium to convey the vibration.

Like all physical phenomena, sounds can be characterized. We can use parameters such as the intensity, the pitch and the timbre to define and distinguish different sounds. Other parameters are possible too – people interpret sounds as they hear them. This involves subjective phenomena, so-called psychoacoustic phenomena, which depend on the physiology, culture and ethnicity of the individuals receiving the sound message. This approach to decrypting the process of sound characterization is highly complex. We will quickly encounter questions to which science has not yet been able to provide comprehensive answers.

Over the centuries, philosophers have often wondered: does a sound exist if no one is there to hear it?

The field of science that studies the physics of sound phenomena is know...

Table of contents

• Cover
• Table of Contents
• Title
• Copyright
• Foreword
• About this Book
• Introduction
• 1 Notes on the Theory of Sound
• 2 Audio Playback
• 3 Types of Effect
• 4 Filtering Effects
• 5 Modulation Effects
• 6 Frequency Effects
• 7 Dynamic Effects
• 8 Time Effects
• 9 Unclassifiables
• Conclusion
• Appendices
• Glossary
• Bibliography
• Index
• End User License Agreement