User guide

Pro Tools|HD User Guide44
Configuring the Pro Tools
Playback Engine
In the Playback Engine dialog, Pro Tools lets you
adjust the performance of your system by
changing system settings that affect its capacity
for processing, playback, and recording. These
system settings are available in the Playback En-
gine dialog (Setup > Playback Engine).
In most cases, the default settings for your sys-
tem provide optimum performance, but you
may want to adjust them to accommodate large
or processing-intensive Pro Tools sessions.
Hardware Buffer Size
The Hardware Buffer Size (H/W Buffer Size) con-
trols the size of the buffer used to handle host
processing tasks such as processing with Real-
Time AudioSuite™ (RTAS) plug-ins.
• Lower Hardware Buffer Size settings are useful
for improving latency issues in certain record-
ing situations or for improving certain system
performance problems:
• On all Pro Tools systems, lower settings re-
duce RTAS MIDI-to-audio latency (such as
when playing an RTAS virtual instrument
live and monitoring the instrument’s out-
put). Lower settings can also improve
screen response or the accuracy of plug-in
and mute automation data.
• On Pro Tools|HD systems specifically,
lower settings reduce monitoring latency
that occurs on tracks that have one or more
RTAS plug-ins. Lower settings can also im-
prove the accuracy of MIDI track timing on
systems without a MIDI interface that sup-
ports time stamping. Lower settings also
improve MIDI track timing on tracks using
MIDI virtual instruments that do not sup-
port time stamping.
• Higher Hardware Buffer Size settings are use-
ful for sessions that are using more RTAS plug-
ins for playback. These settings allow for more
audio processing. They can also be useful to
reduce errors on machines that require a
higher buffer size.
To change the Hardware Buffer Size:
1 Choose Setup > Playback Engine.
2 From the H/W Buffer Size pop-up menu, select
the audio buffer size, in samples.
3 Click OK.
Playback Engine dialog for Pro Tools|HD system