Specifications

4 Introduction
to learn. Althoug h Pur e Data is the main ve hicle for teaching this subject an
attempt is made to discuss the principles in an application agnostic way. Some
of the content is readable and informative without the need for other resources ,
but to make the best use of it you should work alongside a computer set up
as an audio workstation and complete the practical examples. The minimum
system requirements for most examples are a 500MHz computer with 256 MB
of RAM, a so und card, loudspeakers or headphones, and a copy of the Pure
Data program. A simple wave file editor, such as Audacity, capable of handling
Microsoft .wav or Mac .au formats will b e useful.
Structure
Many of the examples follow a pattern. First we discuss the nature and physics
of a sound and talk about our goals and constraints. Next we explore the
theory and gather food for developing synthesis models. After choosing a set
of methods, each example is implemented, proceeding through several stages of
refinement to produce a Pure Data program for the desired sound. To make
good use of space and avoid repeating material I will sometimes present only
the details of a program which change. As an ongoing subtext we will discuss,
analyse and refine the differe nt synthesis techniques we use. So that you don’t
have to enter every Pure Data program by hand the examples are available on
a CD ROM a nd online to download. There are audio examples to help you
understand if Pure Da ta is not available.
Written Conventions
Pure Data is abbreviated as Pd, and since other similar DSP patcher tools exist
you may like to take Pd as meaning “patch diagram” in the widest sense. For
most commands, keyboard shortcuts are given as CTRL+s, RETURN and so forth.
Note, for Mac users CTRL refers to the “command” key and where right click
or left click are specified you should use the a ppropriate keyb oard and click
combination. Numbers are written as floating point decimals almost everywhere,
especially where they r e fer to signals, as a constant reminder that all numbers
are floats in Pd. In other contexts ordinary integers will be written as such.
Graphs are provided to show signals. These are generally normalised −1.0 to
+1.0, but absolute scales or values should not be taken too seriously unless the
discussion focuses on them. Scales are often left out for the simplicity of showing
just the signal. When we refer to a Pd object within text it will appear as a
small container box, like
metro
. The contents of the box are the object name,
in this case a metronome. The motto of Pd is “The diagram is the program”.
This ideal, upheld by its author Miller Puckette, makes Pd very interesting
for publishing and teaching because you can implement the examples just by
looking at the diagrams.