Specifications
Mbox 2 Mini Getting Started Guide14
 A lower number of processors leaves more 
CPU processing capacity for automation, screen 
redraws, and video playback in Pro Tools, or for 
other application running at the same time as 
Pro Tools.
To set the number of RTAS Processors:
1 Choose Setup > Playback Engine.
2 From the RTAS Processors pop-up menu, se-
lect the number of available processors you 
want to allocate for RTAS plug-in processing.
3 Click OK.
CPU Usage Limit
The CPU Usage Limit controls the percentage of 
CPU resources allocated to Pro Tools host pro-
cessing tasks. Used in combination with the 
RTAS Processors setting, the CPU Usage Limit 
setting lets you control the way Pro Tools tasks 
are carried out by the system.
 Lower CPU Usage Limit settings limit the ef-
fect of Pro Tools processing on other CPU-inten-
sive tasks, such as screen redraws, and are useful 
when you are experiencing slow system re-
sponse, or when running other applications at 
the same time as Pro Tools.
 Higher CPU Usage Limit settings allocate 
more processing power to Pro Tools, and are 
useful for playing back large sessions or using 
more real-time plug-ins. 
The maximum available CPU Usage Limit de-
pends on the number of processors in your com-
puter and on the number of processors you spec-
ify for RTAS processing. This value can range 
from 85 percent for single-processor computers 
to 99 percent for multi-processor computers.
To change the CPU Usage Limit:
1 Choose Setup > Playback Engine. 
2 From the CPU Usage Limit pop-up menu, se-
lect the percentage of CPU processing you want 
to allocate to Pro Tools. 
3 Click OK.
RTAS Engine (RTAS Error Suppression)
The RTAS Engine option determines RTAS error 
reporting during playback and recording. This is 
especially useful when working with instrument 
plug-ins.
You should only enable RTAS error suppression 
if you are experiencing frequent RTAS errors 
that are interrupting your creative workflow. 
When RTAS error suppression is enabled, you 
can experience a degradation of audio quality. 
However, this may be acceptable in order to 
avoid interrupting playback and recording 
when working with instrument plug-ins. Be sure 
to disable RTAS error suppression when you 
need to ensure the highest possible audio qual-
ity, such as for a final mix.
There is one RTAS Engine option:
Ignore Errors During Playback/Record When en-
abled, Pro Tools continues to play and record 
even if the RTAS processing requirements ex-
ceed the selected CPU Usage Limit. This can re-
sult in pops and clicks in the audio, but does not 
stop the transport.
To enable RTAS error suppression:
1 Choose Setup > Playback Engine.
2 Select Ignore Errors During Playback/Record.
3 Click OK.
Increasing the CPU Usage Limit may slow 
down screen response on slower computers.










