Modulation Processor Examples - E-Mu ProteusX Operation Manual

9 - Synthesizer Basics
Modulation Processors

Modulation Processor Examples

This example routes the Pink Noise generator through one of the Lag Processors in
order to derive a smooth random function. A smooth random wave is useful in small
amounts to add a degree of natural variation to timbre when routed to filter cutoff.
Normal pink noise is low pass filtered audio frequency noise with a 3 dB/octave slope to
give equal energy per octave. Our pink noise is actually more like very low frequency
filtered (mauve?) noise, but it is perfect for use as a random control source.
Pink
Noise
Cord
The Quantizer can generate interesting whole-tone scales when envelope generators or
LFOs are routed to the input. The quantizer turns a smoothly changing input signal into
a series of steps. By routing the output of the quantizer to Pitch and adjusting the cord
amounts, you can control both the number of steps and the pitch interval of each step.
Number
Steps
Cord
The input cord amount controls how many steps are generated. A sawtooth wave
(LFO+) feeding the input, and the cord amount set to 100% generates sixteen steps. The
output cord amount controls the size (or interval) of the steps.
This patch generates an ascending arpeggio every time you press a key. The block
diagram of the patch is shown below. The patch is very straightforward except for the
DC offset which was added in to bring the pitch down into tune. (Sometimes you have
to fix a problem, but thanks to the mod processors there's usually a way around it to
achieve the desired result.)
Number
LFO+
100%
Cord
You can probably start to see some of the possibilities (and there are many). Whenever
you find yourself wishing for some esoteric type of control, take a minute and think if
there is a way to achieve the desired result using the modulation processors.
152
Lag
Processor
Lag Smooths
Pink Noise
of
Quantizer
Quantizer
DC
Filter
Cutoff
Cord
Smooth
Random Function
Size
of
Steps
Cord
Size
100%
Cord
Cord
-50%
Experiment with this
f
patch by connecting
other sources and
destinations to the
quantizer.
Pitch
Proteus X Operation Manual