5.1 DigiRack Plug-Ins Guide - Digidesign Support Archives

Feedback (FB) Controls the amount of feedback
(positive or negative) applied from the output of
the delay back into its input. This allows you to
control the number of repetitions of the delayed
signal.
The pre/post switch selects whether the feedback
signal is taken pre-mix (wet only) or postmix
(actual output). Post-mix feedback is affected
by the Mix control setting. To see a signal
path diagram illustrating the effect of the
pre/post switches, click on the Procrastinator
logo; it will display the current signal flow. Click
again to return to the logo.
Low Pass Filter (LPF) Controls the cutoff frequency
of the low-pass filter. This allows you to
attenuate the high frequency content of the
feedback signal. The lower the setting, the more
high frequencies are attenuated. Moving the
slider all the way to the right sets it to the off position.
The pre/post switch determines whether
the LPF is pre-feedback (affects the initial delayed
repeat) or post-feedback (affects only the
second and successive repeats).
Tempo-Related Controls
The remaining parameters of the Procrastinator
plug-in provide you with an alternate method
for entering a desired delay value. Rather than
selecting a delay time, it allows you to set a
tempo and the desired number of beats of delay.
Tempo Selects the desired tempo in beats per
minute (bpm). This setting is independent of
Pro Tools’ tempo. When a specific Duration is
selected (see “Duration” below) moving this
control will affect the Delay setting and viceversa.
Likewise, the range of both controls will
be limited to the maximum available delay with
the currently selected Duration. To enter very
slow tempos or short delays it may be necessary
to deselect all Duration buttons.
Duration Specifies a desired delay from a musical
perspective. Using the guideline of one beat is
equal to one quarter note, enter the desired delay
by selecting appropriate durations. You can
enable multiple buttons by Shift-clicking them.
Groove Provides fine adjustment of the delay in
percentages of a sixteenth note. It can be used to
add a groove by slightly offsetting the delay
from the precise beat of the track.
Dither
The Dither plug-in is designed for improved
16-, 18-, or 20-bit performance and reduced
quantization noise when mixing or fading lowlevel
audio signals.
Dither plug-in
Dither is a form of randomized noise used to
minimize quantization errors in digital audio
systems. Quantization distortion is most audible
when the audio signal is near the low end of its
dynamic range, such as during a quiet passage or
fade-out.
The introduction of dithering can reduce these
quantizing errors with very low-level random
noise, minimizing distortion products as audio
reaches low level. With dithering there is a
trade-off between signal-to-noise performance
and less-apparent distortion. Proper use of dithering
allows you to squeeze better subjective
performance out of 16-bits (or whatever your
destination bit-depth is).
Chapter 4: DigiRack Real-Time TDM and RTAS Plug-Ins 37