Specifications

DigiRack Plug-ins Guide80
Delay Provides up to 8192 samples of delay com-
pensation adjustment, or general adjustment of
phase relationships of audio recorded with mul-
tiple microphones, depending on which version
of TimeAdjuster is used. It defaults to a mini-
mum delay of four samples, which is the delay
created by use of the TimeAdjuster plug-in itself.
While phase inversion controls have been used
for many years by engineers as creative tools for
adjustment of frequency response between mul-
tiple microphones, sample-level delay adjust-
ments provide far more control. Creative use of
this control can provide a powerful tool for ad-
justing frequency response and timing relation-
ships between audio signals recorded with mul-
tiple microphones.
Using TimeAdjuster for
Manual Delay Compensation
DSP and host-based processing in all digital sys-
tems incurs delay of varying amounts. You can
use the TimeAdjuster TDM plug-in to apply an
exact number of samples of delay to the signal
path of a Pro Tools track to compensate for delay
incurred by specific plug-ins. TimeAdjuster pro-
vides presets for common delay-compensation
scenarios.
To compensate for several plug-ins in-line, use
the delay times from each settings file as refer-
ences, and add them together to derive the total
delay time.
Alternatively, look up the delay in samples for
the plug-ins you want to compensate for, then
apply the appropriate amount of delay.
To manually compensate for DSP-induced de-
lays, try one of the following methods:
• Phase inversion
– or –
• Comb-filter effect cancellation
Phase Inversion
If you are working with phase-coherent track
pairs, or tracks recorded with multiple micro-
phones, you can invert the phase to negate the
delay. If you don’t hear any audio when you in-
vert a signal’s phase, you have precisely adjusted
and compensated for the delay. This is because
when you monitor duplicate signals and invert
the polarity (phase) of one of them, the signals
will be of opposite polarity and cancel each
other out. This technique is convenient for find-
ing the exact delay setting for any plug-in.
To determine the delay of a plug-in by inverting its
signal phase:
1 Place duplicate audio regions on two different
audio tracks and pan them to the center (mono).
2 Apply the plug-in whose delay you want to
calculate to the first track, and a Time Adjuster
plug-in to the second track.
3 With TimeAdjuster, invert the phase.
4 Control-drag (Windows) or Command-drag
(Mac) to fine-tune delay in one sample incre-
ments, or use the up/down arrow keys to change
the delay one sample at a time until the audio
signal disappears.
Some plug-ins (such as Digidesign’s Maxim
and DINR BNR) have different delays at
different sample rates. Refer to the Digide-
sign Plug-ins Guide for more information
about these plug-ins.
A delay table for DigiRack plug-ins appears
in Appendix B, “DSP Delays Incurred by
TDM Plug-ins.”