OSCILLATORS
Phase Distortion
Like FM,
Phase Distortion
(PD) is another method of skewing sine waves developed during the
1980s. If you’re interested in the technical details, you could start by reading these articles:
http://en.wikipedia.org/wiki/Phase_distortion_synthesis
http://en.wikipedia.org/wiki/Casio_CZ_synthesizers
Whenever you start a fresh instance of BeatZille, the
initialize
patch is automatically loaded. In this
patch, oscillator 1 is already connected to one of the outputs so you can at least hear a sound.
Oscillator 1’s PD knob is set to maximum, resulting in a bright sawtooth-like wave. Try turning this
all the way down for a pure sine wave, then modulate the phase distortion amount by connecting
e.g. envelope 2 to the socket and turning the amount up.
PD / PD modulation
The PD knob controls the basic amount of phase distortion. The bipolar knob to the left adjusts
the modulation depth from any signal connected to the socket.
PD waves
(upper 2 selectors)
The selectors below the PD knob specify a pair of
alternating non-linear phase functions.
The first five modes (
Saw, Square, Impulse, 2pulse,
Halfsaw
) are simple, they need no explanation.
In the three ‘Res’ modes, multiple sine waves are
packed into one of 3 differently-shaped ‘windows’.
The number of cycles in the window is controlled by
the
PD
parameter.
Here are two of the many possible combinations:
Saw + Square
I Res 2
Shape
(lower selector)
Sets the basic oscillator waveform before phase distortion:
Cosine
for regular phase distortion i.e. the above waves
...........
TapMap1
the
as waveform – note that low notes can get gritty due to
........
the lower resolution compared with
Cosine
, and high notes can alias more
21
Saw
Square
Impulse
2Pulse
HalfSaw
Res I
Res II
Res III
