Sound Synthesis Theory/Introduction

Introduction

This book covers a sub-field of Music Technology called sound synthesis. Although the tone is generally aimed at musicians and people with little prior knowledge of music systems, there may be some mathematical concepts and programming techniques that are not familiar. The book focuses on synthesis from a digital perspective rather than an analogue one, since it aims to demonstrate the theory of digital synthesis rather than applications to a specific medium or piece of software.

The Korg MS10 is an example of an early analogue synthesizer.

What is sound synthesis?

Sound synthesis is the technique of generating sound, using electronic hardware or software, from scratch. The most common use of synthesis is musical, where electronic instruments called synthesizers are used in the performance and recording of music. Sound synthesis has many applications both academic and artistic, and we commonly use synthesizers and synthesis methods to:

• Generate interesting and unique sounds or timbres incapable of being produced acoustically.
• Recreate or model the sounds of real-world acoustic instruments or sounds.
• Facilitate the automation of systems and processes (text-to-speech software, train station P.A.s)

Background and history

One of the earliest musical synthesizers was Thaddeus Cahill's Teleharmonium, presented to an audience of about nine hundred in 1906. This massive instrument defined a fundamental synthesis technique called additive synthesis which used combinations of pure tones to generate its sounds. Other early synthesizers used technology derived from electronic analog computers, laboratory test equipment, and early electronic musical instruments. However, it was not until the late 1960s that technology had developed far enough for synthesizers to be a commercial success, most notably with Robert Moog's modular and mini-modular analogue synthesizers.

Since the late 1980's, most new synthesizers have been completely digital. At the same time analogue synthesis has also revived in popularity, so in recent years the two trends have combined in the appearance of virtual analog synthesizers, digital synthesizers of which model analog synthesis using digital signal processing techniques. Digital synthesizers use digital signal processing (DSP) techniques to make musical sounds. Some digital synthesizers now exist in the form of 'softsynth' software that synthesizes sound using conventional PC hardware. Others use specialized DSP hardware.