Sequential Prophet X, User Manual

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50 51 Low Frequency Oscillators Sequential Prophet X User’s Guide Low Frequency Oscillators
Low Frequency Oscillators
The four LFOs are special-purpose oscillators that produce a frequency
that is typically below the range of human hearing (although these can
actually extend into the audio range if set to their maximum frequency).
The LFOs are typically used for periodic modulation such as vibrato
(periodic pitch modulation) and tremolo (periodic amplitude modula-
tion). They can also be used as modulation sources for any of the many
modulatable parameters in the Prophet X.
The LFOs produce a variety of waveshapes, including triangle, sawtooth,
reverse sawtooth, square, and random. Though most often used for low-
frequency modulation, the Prophet X LFOs can actually function at speeds
that extend into the audible range for extreme effects.
The Low Frequency Oscillators
Triangle and Random waves are bipolar. That is, their waveshape is posi-
tive for half of their cycle and negative for the other half. In the case of the
triangle wave, this makes it possible to generate a natural-sounding vibrato
that goes alternately sharp and flat in equal amounts on either side of a center
frequency. Random, also known as “sample and hold,” generates a series
of random values, each held for the duration of one cycle.
The square wave, sawtooth, and reverse sawtooth generate only posi-
tive values. In the case of the square wave this makes it possible to generate
natural-sounding trills.
Square Random Sawtooth Reverse
Sawtooth
Triangle
0
LFO waveshapes
The LFOs can be free-running or synced to the arpeggiator, sequencer, or
MIDI clock for tempo-synced effects such as filter sweeps, tremolo, and so on.
LFO Parameters (Front Panel)
Frequency: Sets the frequency of the selected LFO from a slow .022Hz
to a fast 500Hz. This is affected by the
clk sync
(clock sync) parameter
as explained below.
Amount:
Sets the amount of LFO modulation routed to the selected
destination. Setting an amount here applies the selected modulation
continuously. You can also use the modulation matrix to route an LFO
to additional destinations and use a different modulation amount if you
want.
Shape: Triangle, Sawtooth, Reverse Sawtooth, Square, Random
—This
button sets the waveshape of the selected LFO.