5.1 DigiRack Plug-Ins Guide - Digidesign Support Archives

Pitch Shift Parameters
In addition to the standard AudioSuite functions,
the Pitch Shift plug-in provides the following
parameters:
Gain Adjusts input level, in 10ths of a dB. Dragging
the slider to the right increases gain, dragging
to the left decreases gain.
Coarse and Fine Adjust amount of pitch shift.
The Coarse slider transposes in semitones (half
steps). the Fine slider transposes in cents (hundredths
of a semitone).
Time Correction Disabling this option has the effect
of “permanently varispeeding” your audio
file. The file’s duration will be compressed or extended
according to the settings of the Coarse
and Fine pitch controls. Altering a file in this
way has little detrimental effect on the fidelity
of audio files, whereas time correction can affect
fidelity in a more pronounced way.
Ratio Adjusts the amount of transposition
(pitch change). Moving the slider to the right
raises the pitch of the processed file, while moving
the slider to the left decreases its pitch.
Crossfade Allows you to manually adjust the
crossfade length in milliseconds to optimize
performance of the Pitch Shift plug-in according
to the type of audio material you are processing.
This plug-in achieves pitch transposition by
processing very small portions of the selected
audio material and very quickly crossfading between
these alterations in the waveform of the
audio material.
Crossfade length essentially affects the amount
of “smoothing” performed on audio material to
prevent audio artifacts such as clicks when the
audio is looped to generate the desired pitch
shift. In general, small narrow-range pitch
changes require longer crossfades while larger
transpositions require smaller crossfades. The
disadvantage to long crossfade times is that they
smooth the signal, including any transients.
While this can be desirable for audio material
such as vocals, it is not appropriate for material
with sharp transients such as drums or percussion.
The default setting for this parameter is Auto
(full left), in which crossfade times are set automatically,
according to the settings of the coarse
and fine controls. This setting should be sufficient
for most applications. However, by using
this slider, you can manually adjust and optimize
crossfade times if necessary. For audio material
with sharper attack transients, use smaller
crossfade times. For audio material with softer
attack transients, use longer crossfade times.
Min Pitch Sets the minimum, or lowest, pitch
that will be used in the plug-in’s calculations
during the Time Compression/Expansion process.
The slider has a range of 40 Hz to 1000 Hz.
By being able to control the minimum pitch,
you can focus the Time Compression/Expansion
process for maximum efficiency—it all depends
on the audio’s spectral shape.
This slider should be set lower when processing
bass guitar or other instruments with a similarly
low frequency range. Set this parameter higher
when processing higher frequency range sounds
or instruments.
Accuracy Prioritizes the processing resources allocated
to audio quality (Sound) or timing
(Rhythm). Moving the slider towards Sound
generally results in better sonic quality and
fewer audio artifacts. Moving the slider towards
Rhythm puts the emphasis on keeping the
tempo consistent.
Chapter 5: DigiRack Non-Real-Time AudioSuite Plug-Ins 51