Reference Manual

410 Live Instrument Reference
useful, for example, in creating live drum sounds. Fixed Mode also allows producing very low
frequencies down to 0.1 Hz. Note that when Fixed Mode is active, the frequency of the oscilla-
tor is controlled in the shell with the Frequency (Freq) and Multiplier (Multi) controls.
Operator includes a special Osc<Vel control for each oscillator that allows altering frequency
as a function of velocity. This feature can be very useful when working with sequenced sounds in
which the velocity of each note can be adjusted carefully. Part of this functionality is the adjacent
Q (Quantize) button. If this control is activated, the frequency will only move in whole numbers,
just as if the Coarse control were being manually adjusted. If quantize is not activated, the
frequency will be shifted in an unquantized manner, leading to detuned or inharmonic sounds
(which very well could be exactly what you want...).
The amplitude of an oscillator depends on the Level setting of the oscillator in the shell and on its
envelope, which is shown and edited when the Envelope display is visible. The envelopes can
also be modified by note velocity and note pitch with the Vel and Key parameters available in
the Envelope section of each oscillator’s display.
The phase of each oscillator can be adjusted using the Phase control in its display. With the R
(Retrigger) button enabled, the waveform restarts at the same position in its phase each time a
note is triggered. With R disabled, the oscillator is free-running.
As explained earlier oscillators can modulate each other when set up to do so with the global
display’s algorithms. When an oscillator is modulating another oscillator, two main properties
define the result: the amplitude of the modulating oscillator and the frequency ratio between
both oscillators. Any oscillator that is not modulated by another oscillator can modulate itself, via
the Feedback parameter in its display.
Aliasing
Aliasing distortion is a common side effect of all digital synthesis and is the result of the finite
sample rate and precision of digital systems. It mostly occurs at high frequencies. FM synthesis
is especially likely to produce this kind of effect, since one can easily create sounds with lots of
high harmonics. This also means that more complex oscillator waveforms, such as “Saw 32,“
tend to be more sensitive to aliasing than pure sine waves. Aliasing is a two-fold beast: A bit of
it can be exactly what is needed to create a cool sound, yet a bit too much can make the timbre
unplayable, as the perception of pitch is lost when high notes suddenly fold back into arbitrary
pitches. Operator minimizes aliasing by working in a high-quality Antialias mode. This is on by
default for new patches, but can be turned off in the global section. The Tone parameter in the
global section also allows for controlling aliasing. Its effect is sometimes similar to a lowpass