Specifications

Pro Tools Reference Guide592
3 Control-click (Windows) or Command-click
(Macintosh) the track’s Volume Indicator until
the Channel Delay value is displayed for that
track.
4 Change the delay time in TimeAdjuster by
moving the Delay slider or entering a value in
the Delay field, until the track delay value
matches that of the first track.
You can test the delay values by duplicating an
audio track and reversing its phase while com-
pensating for delay.
If you are using a plug-in whose delay factor you
are not familiar with, you can set the delay by
ear using one of two methods:
• If you are working with phase-coherent track
pairs, or tracks that had been multi-miked,
you can “null out” the delay. Invert the phase
of the target track using the TimeAdjuster
Phase Invert button, and adjust the plug-in
delay time until the signal disappears. (When
they are perfectly synchronized, duplicate sig-
nals of opposite polarity cancel each other
out.) When you are finished, disengage the
Phase Invert button.
– or –
• Change the delay while listening to the signal
in phase, adjusting until any comb-filter ef-
fects cancel out.
Nudging Audio Tracks
On audio tracks, you can use the Pro Tools
Nudge feature to nudge the affected regions in
single-sample (or other) increments, to preserve
phase coherency. If it is necessary to nudge a re-
gion by a large number of samples, you may
want to calculate the equivalent value in milli-
seconds and nudge the Region in millisecond
increments. If the value doesn’t divide evenly,
you can switch the Nudge value back to samples
and use these smaller increments for the re-
mainder.
The disadvantage of using this method is that it
only works with audio tracks (not live inputs),
and the timing relationship between tracks is
permanently altered, which can affect editing.
Sample Rate and How it Affects Delay
The delay in samples caused by TDM processing
is the same regardless of the sample rate because
a sample is tied to the rate of the sample clock
for the entire system. However, when samples
are converted into a time value (milliseconds or
microseconds), the sample rate (44.1 versus
48 kHz) must be taken into account.
Delay Factors
In Pro Tools TDM systems, delay is incurred
when you perform the following processes:
• Real-time processing (plug-in inserts). See
“Using Plug-In Inserts” on page 593.
• Mixing and routing (sends and hardware
inserts). See “Using Sends and Hardware In-
serts” on page 593.
• Bouncing tracks. See “Bouncing Tracks” on
page 594.