ABSTRACT
In this chapter we describe how music is created by audio synthesis. We will concentrate on how spectrograms can be used for synthesizing music, by the method of granular synthesis. Granular synthesis underlies the AUTOTUNER musical synthesizer. AUTOTUNER’s granular synthesis is also known as phase vocoding. A phase vocoder was used by Imogen Heap to create her song, Hide and Seek. We will discuss this song in Section 8.2. Granular synthesis is also used for time-stretching and time-shrinking of musical sound without changing pitch. We will provide some musical examples of time-stretching and time-shrinking in Section 8.3. The chapter concludes with an entirely different synthesis method: MIDI synthesis. MIDI synthesis is widely employed for computer scoring programs. Although it does not typically have the flexibility of granular synthesis, it does have the advantage of more clearly relating to standard musical composition.
