User Manual

Pro Tools Reference Guide10
Digidesign Audio Engine
The Digidesign Audio Engine (DAE) is a real-
time operating system for digital audio record-
ing, playback, and processing. When you install
Pro Tools, DAE is automatically installed on
your system.
In the same way that a computer’s operating sys-
tem provides the foundation for programs that
run on the computer, DAE provides the founda-
tion for much of the hard disk recording, digital
signal processing, and mix automation required
by Pro Tools and other products from Avid and
its Development Partners.
The DAE Playback Buffer Size determines the
amount of memory DAE allocates to manage
disk buffers. The DAE Playback Buffer Size can
be changed in the Playback Engine (see “DAE
Playback Buffer Size” on page 67
).
Playback Engine
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 Engine (Setup > Playback Engine).
Pro Tools takes advantage of your computer’s
host processor for certain tasks and optional
host-based DSP processing.
Pro Tools uses host (CPU) processing to provide
audio track recording, playback, mixing, and ef-
fects processing. Both Pro Tools and Pro Tools
HD use host processing to run RTAS
®
(Real-Time
AudioSuite) plug-ins for effects processing. Per-
formance is determined by your system and its
Playback Engine settings.
The Playback Engine lets you set a hardware
buffer size and allocate a percentage of CPU
resources for these tasks.
On Pro Tools|HD systems, you can select the
number of voices and voiceable tracks for your
system and its sessions. Voice count choices are
based on how much DSP processing you want to
allocate for voicing.
The Playback Engine is also where you assign
dedicated resources for Automatic Delay Com-
pensation.
Playback Engine for Pro Tools|HD system
For more information, see “Configuring
Pro Tools System Settings” on page 60. See
also “System Resources” on page 21.