E-Mu ProteusX, Operation Manual

Page: 148 / 188

9 - Synthesizer Basics
Random Sources
148 Proteus X Operation Manual
When the amount of an LFO is a negative value, the LFO shape will be inverted. For
example, inverting the sawtooth wave produces a wave that smoothly increases, then
instantly resets down. Since the inverted sawtooth wave is now negative, adding DC
with a cord amount of +100 will make it positive again. See
page 152 for information
on how to use a DC Cord.
Random Sources
Random modulation sources can be used when you want the timbre of the sound to be
“animated” in a random or non-consistent manner.
Key Random 1 & 2 generate different random values for each voice which are selected at
key-on time and do not change during the note.
The White & Pink Noise Generators produce varying random values. Both white and
pink noise sources are low frequency noise designed for control purposes. Either noise
source can be filtered even more by passing it through a lag processor.
The Crossfade Random function generates the same random value for all voices in a
preset. This source is designed to be used for randomly crossfading voices, although you
may find other uses.
Clock Modulation
The clock can also be used as a modulation source. It can be used to trigger the Filter or
Auxiliary envelope generators, trigger sample start, synchronize the LFOs, or used
directly as a square wave modulation source. Envelopes are triggered on the positive
going edge of the clock. LFOs are triggered on the negative going edge.
E
Envelopes are
triggered on the positive
going edge of the clock.
LFOs are triggered on the
negative going edge of
the clock.
The Clock source is available in six divisions (double whole note, whole note, half note,
quarter note, eighth note, sixteenth note). The different rates can be used separately or
in conjunction to create complex “synchro-sonic” rhythm patterns.
Using MIDI clocks, the internal clock can also be synchronized with an external MIDI
device such as a drum machine or sequencer.
E The tempo of the
master clock is set from
the Multisetup page.
Clocks are routed exactly like the other modulations sources using the Cords. The Cord
Amount MUST be positive (+) for the clock to pass. By modulating the Cord Amount,
the divided clocks can be routed around using realtime controllers or other modulation
sources.
Syncing an LFO to the Clock
When an LFO is triggered by a clock, the LFO wave resets to zero every time the clock
wave goes low. To sync an LFO to the clock, patch a clock divisor to the LFO Trigger
(Trg) in the Cords screen.
If the LFO rate is close to the clock rate, the LFO will synchronize with the clock. If the
two rates are far apart, the waveform of the LFO will be mildly or radically altered (as
shown by the diagram on the following page).