DigiDesign DigiRack, Manual

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Chapter 6: DigiRack Real-Time TDM and RTAS Plug-ins 89
Ratio Indicates the ratio of transposition be-
tween the original pitch and the selected trans-
position value.
Crossfade Adjusts crossfade length in millisec-
onds to optimize performance of the Pitch plug-
in according to the type of audio material you
are processing. The Pitch plug-in performs pitch
transposition by replicating or subtracting por-
tions of audio material and very quickly cross-
fading between these alterations in the wave-
form of the audio material.
Crossfade length affects the amount of smooth-
ing performed on audio material to prevent au-
dio artifacts such as clicks from occurring as the
audio is looped to generate the pitch shift.
In general, small, narrow-range pitch shifts re-
quire longer crossfades and large shifts require
smaller ones. The disadvantage of a long cross-
fade time is that it will smooth the signal, in-
cluding any transients. While this is sometimes
desirable for audio material such as vocals, it is
not appropriate for material with sharp tran-
sients such as drums or percussion.
The default setting for this control is Auto. At
this setting, crossfade times are set automati-
cally, according to the settings of the Coarse and
Fine pitch controls. The Auto setting is appro-
priate for most applications. However, you can
manually adjust and optimize crossfade times
using the Crossfade slider if necessary. For audio
material with sharper attack transients, use
shorter crossfade times. For audio material with
softer attack transients, use longer crossfade
times.
Minimum Pitch Sets the minimum fundamental
pitch that the Pitch plug-in will recognize when
performing pitch transposition. Use this to opti-
mize the Pitch plug-in’s performance by adjust-
ing this control based on the lowest fundamen-
tal pitch of the audio material that you want to
process.
On audio material with a low fundamental
pitch frequency content (such as an electric bass
guitar) setting this control to a lower frequency
such as 30 Hz will improve the Pitch plug-in’s
performance. The most important thing to re-
member when using this control is that the fun-
damental frequency of audio material you want
to process must be above the frequency you set
here.
The range of this slider is from 15 Hz to 1000 Hz.
The default setting is 60 Hz. Adjustment is tied
to the current setting of the Maximum Pitch
control so that the minimum range is never less
than one octave, and the maximum range never
more than five octaves.
Maximum Pitch Adjusts the maximum funda-
mental pitch that the Pitch plug-in will recog-
nize when performing pitch transposition. To
optimize the Pitch plug-in’s performance, adjust
this setting (and the Minimum Pitch setting)
based on the highest fundamental pitch of the
audio material that you want to process. The
range of this slider is from 30 Hz to 4000 Hz. The
default setting is 240 Hz.