Specifications

Appendix B: TDM Mixing and DSP Usage 603
I/O
(Pro Tools MIX-Series and Pro Tools|24 Only)
If the DSP is also being used for I/O processing,
then some of the chip’s capacity will be devoted
to I/O, yielding slightly lower mixer count
(these figures represent maximum numbers
when I/O is declared in the Hardware Setup dia-
log):
48-Bit Mixing Precision
The Pro Tools mixer plug-ins use a register area
inside of the DSPs on the hardware to hold a full
48-bits of precision when mixing signals to-
gether. This allows a fader to be lowered in level
without any loss of resolution. (Even if the fader
is lowered almost to the bottom, all 24 of the
original 24 bits of the signal are preserved.)
Mixer Headroom
Use of 48-bit precision when mixing allows the
mixer to be designed to provide a very large
amount of headroom, which allows the faders
on the Pro Tools mixer to be placed in the
“sweet spot” position without clipping.
MIX Card
Mixer Usage
16-bit & 24-bit opti-
mized, mono
59x2 per chip
16-bit & 24-bit opti-
mized, stereo
29x2 per chip
Surround, 5.1 17x6 per chip
Surround, 7.1 12x8 per chip
Usage with other Surround mixer versions varies
with the number of channels in each format.
DSP Farm with one I/O Declared
Mixer Usage
16-bit optimized mono 30x2 per chip
16-bit optimized stereo 15x2 per chip
24-bit optimized mono 20x2 per chip
24-bit optimized stereo 10x2 per chip
Note: The Surround mixer cannot run on DSP Farms,
or any DSP that has I/O declared.
MIX Card with one I/O declared
Mixer Usage
16-bit & 24-bit opti-
mized, mono
51x2 per chip
16-bit & 24-bit opti-
mized, stereo
25x2 per chip
Note: The Surround mixer cannot run on a MIX card
with I/O declared.
MIX Card with two I/Os declared
Mixer Usage
16-bit & 24-bit opti-
mized, mono
43x2 per chip
16-bit & 24-bit opti-
mized, stereo
21x2 per chip
Note: The Surround mixer cannot run on a MIX card
with I/O declared.