1.
Introduction
2. The Musical Environment
3. Loudness and Dynamics
4. Crescendo and Diminuendo
5. Sound Envelopes
6. Foreground - Background
7. Listening Structures
8. Notating Sounds
9. The Listening Space
10. Radio Composition
11. The Design Team
Sounds constantly change in their loudness levels. Our whole world is one sonic landscape in which sounds recede and move closer. Our survival depends on our ability to detect sound movement. One common way of detecting sound movement is perceiving sounds becoming louder or softer. In music the movement or change from one dynamic level to another involves the following two terms:
| crescendo: becoming louder and is represented by the sign: |  |
| decrescendo or diminuendo: becoming softer and is represented by the sign: |  |
The attack time of crescendo is incremental as it begins at a softer dynamic level moving to a louder level. The above graphic representation of a sound getting louder is an example of a crescendo. Conversely the decay of a decrescendo moves from something loud to soft. Many pieces of music explore combinations of these two simple sound structures to create complex sound structures. Any passing car or overhead plane is a good example of crescendo and decrescendo as example one demonstrates.
EXAMPLE ONE
The sound of an aeroplane passing overhead
In example two the composer has overlaid varying crescendo shapes by having his guitar undergo an electronic process that enables crescendo and decrescendo sound shape to be formed on each guitar note. The overlaying of the different lengths of crescendo and decrescendo shapes produces subtle undulating waves of sounds.