10.6

222Logic Pro Effects
Modulation effects
Logic Pro Modulation effects overview
Modulation effects—such as chorus, flanging, tremolo, and phasing—are used to
add motion and depth to your sound. Perceived width can be altered with the Logic Pro
Spreader effect. Both motion and space can be introduced with the Rotor Cabinet effect.
Modulation effects typically delay the incoming signal by a few milliseconds and use an
LFO to modulate the delayed signal. The LFO may also be used to modulate the delay
time in some effects.
A low frequency oscillator (LFO) is similar to the sound-generating oscillators in
synthesizers, but the frequencies generated by an LFO are so low that they can’t be
heard and are therefore used only for modulation purposes. LFO parameters include
speed (or frequency) and depth—also called intensity—controls.
You can also control the ratio between the affected (wet) signal and the original (dry)
signal. Some modulation effects include feedback parameters, which add part of the
effect output back into the effect input.
Other modulation effects involve pitch. The most basic type of pitch modulation effect
is vibrato, which uses an LFO to modulate the frequency of the sound. Unlike other pitch
modulation effects, vibrato alters only the delayed signal.
More complex modulation effects, such as Ensemble, mix several delayed signals with
the original signal. Ringshifter combines a ring modulator with a frequency shifter effect.
Logic Pro Modulation Delay allows flanging and chorus effects, emulations of tape speed
fluctuations and metallic, robot-like modulations.