User`s guide

Pro Tools Reference Guide384
We refer to certain mixing or signal pro-
cessing functions as “using one DSP” or
“using two DSPs.” This refers to the fact
that there are a certain number of DSP
chips on a card (six on a MIX card, or four
on a DSP Farm card), each of which can
only power a certain number of processing
functions. If you have a single MIX card or
DSP Farm card, and you create a big
enough TDM mixer and use enough Sends
or Plug-Ins, you will eventually use up or
“max out” all DSPs and will be at your limit
for mixing and processing (unless you add
more cards to your system).
Mixing and DSP Usage
Pro Tools builds a TDM mixer every time a
session is opened. Note that the term
“mixer channel” applies to Audio tracks
(including virtual tracks) and Auxiliary In-
put tracks, as well as sends and returns that
use any of the 32 TDM internal busses.
When you go beyond a certain number of
mixer channels, Pro Tools will use another
DSP to create additional mixer capacity.
With Pro Tools 24 and Pro Tools III sys-
tems, Pro Tools does not always automati-
cally free up all unused DSP power when
you delete unneeded mixer channel. On
these systems, to reclaim all DSP power af-
ter a change in your session configuration,
close your session and reopen it. Pro Tools
will rebuild your new mixer configuration
to use DSP power with maximum effi-
ciency.
DSP Manager
(Pro Tools 24 MIX/MIXplus Systems Only)
Pro Tools software (version 4.3 and higher)
includes DSP Manager, a software compo-
nent that optimizes the use of DSP capacity
on Pro Tools 24 MIX/MIXplus systems.
When you have a MIX card in your system,
if your current DSP usage is approaching
the capacity of the card, and you then try
to add a mixer channel or instantiate a
Plug-In, the DSP Manager will automati-
cally try to make room for the new mixer or
Plug-In on the MIX card. It does this by re-
allocating the existing TDM mixers and
Plug-Ins to use the available DSP capacity
on the MIX card as efficiently as possible.
Monitoring DSP Usage
To monitor the usage of DSP resources dur-
ing a Pro Tools session, choose Windows >
Show DSP Usage.
To display DSP resources in different for-
mats, choose Display > DSP Usage Window
Shows and choose a format from the Dis-
play menu.
As you allocate DSP to mixing or process-
ing with Plug-Ins, the DSP Usage window
indicates when DSP chips are available and
when they are in use. Green indicates a
chip is free. Red indicates a chip is in use.
DSP Usage window showing Large format