Audio Damage Phosphor - Manual (Page 5)

Introduction
Phosphor is a polyphonic software synthesizer plug-in modeled on the alphaSyntauri hardware synthesizer.
Introduced in 1979, the alphaSyntauri used an Apple ][ microcomputer as its central processor and user
interface. While quite modest by contemporary standards, the alphaSyntauri can create a surprising wealth of
sounds easily, thanks to its simple but flexible approach to synthesis.
Rather than mimicking the small number of wave shapes available from the oscillators found in analog
synthesizers, the alphaSyntauri’s oscillators used tables of numbers—essentially samples of a single cycle of
an audio wave. The tables are filled with a process known as additive synthesis. The basic idea of additive
synthesis is that any sound wave can be created by adding together a large number of sine waves of different
frequencies. Each sine wave has a pure sound with no harmonics, but if you add a bunch of them together you
can create complex sounds. If you use enough sine waves, and if you control their relative loudness precisely
over the duration of a note, you can recreate just about any sound.
1
Since the alphaSyntauri was limited by the computational power available in its day, it took a relatively simple
approach to additive synthesis. Each oscillator’s wave shape was created by adding together 16 sine waves,
which we’ll henceforth refer to as partials. The wave shape could not change over the duration of a note, but
each oscillator’s overall loudness was controlled by a separate envelope generator, and hence the timbre of
the note could be varied by mixing the two oscillators dynamically. Phosphor reproduces this system faithfully
and adds a couple of tricks of its own.
Phosphor harkens back to a time when high-quality digital synthesis was available only to people with huge
budgets or access to academic research facilities, but low-quality digital synthesis was finding its way into the
public ear through quarter-munching video games and 8-bit home computers. We hope you enjoy using it as
much as we enjoyed building it.
If You Don’t Like To Read Manuals
We understand. You just got a shiny new plug-in and you’d really rather play with it than read some dull
exposition about it. Go ahead, then—install it, load it up, flip through the presets, move some of the controls
around. Phosphor comes with a healthy assortment of built-in presets that will provide instant gratification
and keep you amused for quite some time. When you’re ready to dig deeper and create your own sounds, a
quick read of this manual should help you along.
1 For an in-depth explanation of how this works, see http://en.wikipedia.org/wiki/Additive_synthesis