User`s manual

4.1.5 Modulators
Modulators provide signals that are designed specifically to control the behavior of
oscillators, filters and amplifiers. Unlike audio oscillators, modulators are low-
frequency signals. For example, when you sing with vibrato, you are “modulating”
your voice with a low-frequency change in pitch, typically around 5Hz or so. The
tremolo circuit in a guitar amplifier modulates the amplifier’s level.
Modulators are useful to create dynamic pitch changes (like “wobulation” or
creating chirps), timbre sweeps, and level variations. The main modulators are the
LFO (low frequency oscillator) and envelope generator, but they can also be
provided by external sources that generate control voltage (CV) signals that
provide modulation, and gate signals that turn modulators or notes on and off.
An LFO is low frequency oscillator that can produce various waveforms at sub-
audio frequencies (0.05Hz up to 100Hz). In general the waveform options are sine,
sawtooth, square, random steps, and random waves. These waves’ amount and
polarity (i.e., whether they go positive or negative) can be controlled before being
fed to the target devices.
Contrary to an LFO, an envelope generator (or ADSR generator, for “Attack /
Decay / Sustain / Release”) does not provide a repeating pattern but is controlled
by the keyboard or Gate input. Pressing down a key or sending a gate signal
provides an evolving signal with four different stages:
• The attack stage determines how long it takes for the envelope to go from
zero to its maximum level. The attack time can be as short as 1ms or as long
as 10 seconds.
• The decay stage begins when the attack stage reaches its maximum value,
and determines the time it takes to decrease from this maximum value
down to a steady level (set by the sustain parameter; see next). The speed
of this decay can vary from 1ms to 10 seconds.
Arturia MiniBrute SE User's Manual 26 4 General description