User guide

Chapter 6: Configuring Your Pro Tools System 47
Number of Voices
The Number of Voices setting lets you control the
number of voices available on your system. For
example, the default number of voices on an
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 current sample rate and the
number of cards in your system, and whether
you are using an expansion chassis, you will
have different choices for voice count.
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 choosing a value from the
Number of Voices pop-up menu.
• Select minimum voice numbers if you are
using high-bandwidth PCI or PCIe cards
(such as video capture cards) along with
your Pro Tools|HD cards. These settings
place the lightest processing load on each
allocated DSP chip, but generally require
more DSP chips be dedicated to voicing
and mixing (leaving fewer available for
plug-ins).
• Select medium voice numbers when your
Pro Tools|HD cards are in an expansion
chassis, or when you are using other PCI or
PCIe cards along with Pro Tools|HD cards.
These settings generally provide an opti-
mum balance 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 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.
Default Sample Rate
The Sample Rate setting determines the default
sample rate when you create a new session. This
setting is available only when there is no session
open. Otherwise, the current session sample rate
is displayed, but cannot be changed.
To change the default Sample Rate in the
Playback Engine:
1 Choose Setup > Playback Engine.
2 Select the sample rate from the Sample Rate
pop-up menu.
3 Click OK.
For additional information on voice count,
see the Pro Tools Reference Guide.
The Sample Rate setting can affect the
number of available voices.
You can change the sample rate when
creating a new Pro Tools session by
selecting a different sample rate in the
New Session dialog.
You can also change the default Sample
Rate in the Hardware Setup, as long as no
session is open.