Specifications

Pro Tools Reference Guide590
In simple terms, DSP-induced delay can cause
channels to arrive at the main output (or a sub-
mix output) at different times. To maintain time
alignment, you can compensate for DSP-induced
delays.
When to Compensate
You may only really need to compensate for de-
lays between tracks where phase coherency
must be maintained (as with instruments re-
corded with multiple microphones or stereo
pairs). If you are working with mono signals,
and the accumulated delays are small (just a few
samples, for example), you probably needn’t
worry about delay compensation.
However, larger sessions with higher track and
voice counts, many plug-ins, and/or complex
mixer routing can benefit when DSP-induced
delays are compensated to maintain proper time
alignment.
In any session, if you want to maintain absolute
time alignment across all tracks you should al-
ways compensate for signal processing delays.
Overview of Delay Compensation
Options
Pro Tools provides tools to compensate for sig-
nal processing delays including Automatic De-
lay Compensation (Pro Tools|HD only), as well
as several forms of manual delay compensation.
To compensate for offsets incurred by process-
ing delays, do any of the following (as available
on your system):
Pro Tools|HD (6.4 and Higher) Automatic Delay
Compensation lets Pro Tools automatically cal-
culate and compensate for processing delay. See
“Delay Compensation” on page 590.
All Systems Whenever Automatic Delay Com-
pensation is not available, you can do one or
more of the following:
• Apply sample-level delay to tracks with the
TimeAdjuster plug-in (see “Using the Time-
Adjuster Plug-In” on page 591).
• Manually nudge tracks earlier or later in
time as needed “Nudging Audio Tracks” on
page 592.
•Use the same plug-ins on all tracks.
While learning about delay compensation, keep
in mind that the best results can be often ob-
tained by using a combination of one or more
methods. Doing so gives you more options for
managing DSP resources as needed by Auto-
matic Delay Compensation and the TimeAd-
juster (TDM) plug-in. In addition, the variety of
tools available for delay compensation help en-
sure compatibility if the session is to transferred
to another system.
Delay Compensation
Delay Compensation is used to manage DSP de-
lays that occur on audio tracks, Auxiliary Inputs,
or Master Faders because of plug-in use and
mixer routing. Pro Tools maintains time-align-
ment between tracks that have plug-ins with
differing DSP delays, tracks with different mix-
ing paths, tracks that are split off and recom-
bined within the mixer, and tracks with hard-
ware inserts.
To maintain time alignment, Pro Tools adds the
exact amount of delay to each track necessary to
make that particular track’s delay equal to the
delay of the track that has the longest delay.
Delay Compensation should be enabled during
mixing and playback for optimal delay compen-
sated sound. In some cases when recording, De-
lay Compensation should be turned off.