Checking an hd system with digitest, Configuring pro tools system settings – M-AUDIO Pro Tools Recording Studio User Manual
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Pro Tools Reference Guide
42
4
Do one of the following depending on your
Pro Tools system:
• For Pro Tools|HD systems, turn off your
Pro Tools audio interfaces.
– or –
• For Pro Tools LE and M-Powered systems
that use hardware requiring external power 
(such as 003), turn off the hardware.
5
For Pro Tools|HD systems with an expansion
chassis, turn off the chassis.
6
Turn off any MIDI interfaces, MIDI devices, or
synchronization peripherals.
7
Turn off any worksurfaces (such as
D-Command) or control surfaces (such as 
Command|8).
8
Turn off any external hard drives.
Checking an HD System with 
DigiTest
Before you use Pro Tools, you may want to run 
the DigiTest diagnostic application to ensure 
that all Pro Tools|HD cards in the system are rec-
ognized, installed in the proper order, and have 
valid TDM FlexCable connections. See the HD 
Setup Guide for more information.
Configuring Pro Tools System 
Settings
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 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 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 LE systems, lower settings re-
duce all input-to-output monitoring la-
tency on any record-armed tracks or 
Auxiliary Input tracks with live inputs.
• On Pro Tools HD systems, lower settings re-
duce monitoring latency that occurs on 
tracks that have one or more RTAS plug-ins. 
Lower settings can also improve the accu-
racy of MIDI track timing on systems with-
out a MIDI interface that supports time 
stamping . Lower settings also improve 
MIDI track timing on tracks using MIDI 
virtual instruments that do not support 
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.
