User manual

324
Audio processing and functions
About time stretch and pitch shift algorithms
If you select the “Standard – Custom” option, a dialog opens where you can manually
adjust the three parameters that govern the sound quality of the time stretching:
Limitations
Applying time stretching or pitch shifting to audio material can lead to a degradation in
audio quality and to audible artifacts. The result depends on many factors, such as the
source material, the particular stretch and pitch operations applied, and the selected
audio algorithm preset.
As a rule of thumb, smaller changes in pitch or duration cause less degradation.
However, there are additional issues one should be aware of when working with time
stretching and pitch shifting algorithms.
Ö In rare cases, editing warped audio events may cause discontinuities at the edit
points. You can then try to move the edit point to a different position or bounce the
audio event prior to editing.
Reverse playback and scrubbing
Most of the algorithms used for time stretching and pitch shifting only support forward
playback. Reverse playback or scrubbing of warped audio events can lead to
recurring artifacts in the playback.
Pitch and stretch factor limitations
Some algorithms may put limitations on the maximum degree of time stretching or
pitch shifting supported. For the élastique presets, the maximum pitch shift factor is 4,
and the stretch factor is limited to 10. In case your settings cause a higher factor,
Cubase displays a warning message and deactivates the algorithm for the affected
events until the settings are changed to stay within the valid bounds.
Standard –
Custom
This preset allows you to manually tweak the time stretching
parameters (see below). By default, the settings that are shown when
you open the dialog are those of the last preset used (except if the
Solo preset has been selected, see below).
Standard –
Solo
This mode preserves the timbre of the audio. Only use it for
monophonic material (solo woodwind/brass instruments or solo
vocals, monophonic synths or string instruments that do not play
harmonies).
Parameter Description
Grain size The standard time-stretching algorithm splits the audio into small
pieces called “grains”. This parameter determines the size of the
grains. For material with many transients, use low grain size values for
best results.
Overlap Overlap is the percentage of the whole grain that will overlap with
other grains. Use higher values for material with a stable sound
character.
Variance Variance is also a percentage of the whole length of the grains, and
sets a variation in positioning so that the overlapping area sounds
smooth. A Variance setting of 0 will produce a sound akin to time
stretching used in early samplers, whereas higher settings produce
more (rhythmic) “smearing” effects but less audio artifacts.
Option Description