Apple Logic Pro X - Manual (Page 388)

Chapter 14 Edit the timing and pitch of audio 388
You can also slice an audio region at transient marker positions, splitting it into multiple regions.
You do this by Control-clicking the audio region, then choosing Slice at Transient Markers from
the shortcut menu.
Use the Rhythmic algorithm
m Choose Flex Time - Rhythmic from the Flex pop-up menu.
Rhythmic time stretches the material, looping audio between slices in order to fill any gaps.
This algorithm is most suitable for material such as rhythmic guitars, keyboard parts, and
Apple Loops. Rhythmic comes with the following parameters:
•
Loop Length: Sets the length of the looped section at the end of a slice that is used for
time expansion.
•
Decay: Defines a decay value for the looped area.
•
Loop Offset: Allows you to move the looped area up to 100 ms to the left, preventing pre-
attack sounds from the following transient to appear in the looped and crossfaded area.
Use the Monophonic algorithm
m Choose Flex Time - Monophonic from the Flex pop-up menu.
Monophonic is designed to be used on melodic instruments only playing a single note at a time,
and is therefore good for solo vocals and monophonic solo instruments—melody and bass lines,
for example. When you use this flex algorithm, your recording should be relatively dry, without
audible reverberation. Otherwise, you may want to try using Polyphonic. Monophonic comes
with a single parameter:
•
Percussive: Preserves the area around transient markers to protect the percussive part of the
sound. If selected, allows better timing for all kinds of percussive monophonic tonal material,
such as plucked strings (guitar, bass) or tonal percussion. If unselected, prevents glitches on
transient markers in nonpercussive tonal material, such as bowed strings or wind instruments.
Use the Polyphonic algorithm
m Choose Flex Time - Polyphonic from the Flex pop-up menu.
Polyphonic time stretches material based on a process called phase vocoding—a process that
uses phase information to time stretch an audio signal without touching its pitch. It is the most
processor intensive of all the flex algorithms, but it delivers high sonic quality with suitable
polyphonic material. It’s recommended for complex polyphonic material and is good for all kinds
of chords—such as guitar, piano, and choir—and also complex mixes. Polyphonic comes with a
single parameter:
•
Complex: Enables more internal transients in the audio material.
Use the Tempophone algorithm
m Choose Flex Time - Tempophone (FX) from the Flex pop-up menu.
Tempophone emulates the effect of an historical tape-based time-stretching device known as
a tempophone, and results in a mechanical sound with many artifacts similar to those produced
with granular synthesis techniques. Tempophone is intended to be used creatively for special
effects and comes with the following parameters:
•
Grain Size: Sets the size of the grains that are played or repeated in their original speed and
crossfaded to create time compression or expansion.
•
Crossfade: Adjusts the crossfade length from 0.00, which produces hard artifacts, to the full
grain length of 1.00, which tends to sound softer.