DigiDesign Digidesign Pro Tools 8.0, Reference Manual

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Pro Tools Reference Guide 46
Number of Voices
(Pro Tools HD Only)
On Pro Tools|HD systems, the
Number of Voices
setting lets you control the number of available
voices and how those voices are allocated to
DSPs in your system. For example, the default
number of voices on a Pro Tools|HD 1 system is
48 voices, using one DSP (at sample rates of
44.1 kHz or 48 kHz).
Changing the number of voices affects
DSP usage, the total number of voiceable tracks,
and overall system performance.
Depending on the session sample rate and the
number of Pro Tools|HD cards in your system,
there are different choices for voice count. For
voice limits on different Pro Tools|HD systems,
see “Pro Tools|HD System Playback, Recording
and Voice Limits” on page 31.
To change the Number of Voices and DSP to
allocate for voicing:
1
Choose Setup > Playback Engine .
2
Select the number of voices and DSPs to allo-
cate for voicing by selecting a value from the
Number of Voices pop-up menu as follows:
• Select minimum voice numbers if you are
using high-bandwidth PCI or PCIe cards
(such as video capture cards) along with
your Digidesign cards. These settings place
the lightest processing load on each allo-
cated DSP chip, but generally require more
DSP chips be dedicated to voicing and mix-
ing (leaving fewer available for plug-ins).
• Select medium voice numbers when your
Digidesign cards are in an expansion chas-
sis, or when you are using other PCI or PCIe
cards along with Digidesign cards. These
settings generally provide an optimum bal-
ance between number of chips needed for
voicing, and the processing load placed on
each.
• Select higher voice numbers when your
Pro Tools|HD cards are the only PCI or PCIe
cards in your computer, or when you are
using an expansion chassis to run higher
track counts (such as 64 tracks at 96 kHz)
and you want more voices per DSP (such as
16 voices per DSP at 96 kHz). These settings
use fewer DSP chips for mixing (leaving
more available for plug-ins) but place the
highest processing load on each.
3
Click
OK
.
Number of Voices menu (HD Accel-equipped system)