DigiDesign Pro Tools, Reference Manual

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Pro Tools Reference Guide 744
Dither and Bounce to Disk
Dithering can significantly improve audio qual-
ity. Generally, dithering is necessary when re-
ducing the bit depth for digital audio.
If you use Bounce to Disk, it is important to un-
derstand that the Bounce to Disk process does
not apply dither.
To dither a bounce file, you should insert one of
the included Digidesign Dither plug-ins, or an-
other dithering plug-in, on a Master Fader as-
signed to the bounce source path. Master Faders
are often preferable to Auxiliary Inputs because
Master Fader inserts are post-fader (better for
dithering).
If you do not use a dithering plug-in on your
bounce source path, and you choose to convert
to a lower resolution during or after a Bounce to
Disk, the resultant file will be converted by trun-
cation.
When to Use a Dithering Plug-in
You should use a dithering plug-in in any situa-
tion where you are reducing bit depth, for exam-
ple, when mastering to a 16-bit file with the
Bounce to Disk command, or when mastering to
an external device that records at 16-bit.
This is even necessary when using 16-bit ses-
sions. Even though 16-bit sessions use 16-bit
files, they are still being processed at a higher bit
rate:
• 24-bit audio input and output signal paths
with internal 48-bit mixing and processing for
Pro Tools|HD systems
• 24-bit audio input and output signal paths
with internal 32-bit floating point processing
for Pro Tools LE systems
For this reason, whether you are using a 16-bit
session or a 24-bit session, it is recommended
that you use a Dither plug-in when mastering to
16-bits.
When mastering to 24-bits, it is not necessary to
use a Dither plug-in.
Using Dither on an Output Mix
Pro Tools includes real-time dithering plug-ins
that improve 16-, 18-, or 20-bit performance
and reduce quantization noise when mixing or
fading low-level signals.
The dithering plug-ins have no user-selectable
controls other than Bit Resolution and Noise
Shaping controls.
To use a dithering plug-in on a submix:
1
Choose Track > New and select Master Fader
(stereo) from the pop-up menu.
2
Set the output of the Master Fader to the out-
put or bus path you want to bounce.
3
Assign the outputs of all audio tracks in the
session to the same path you selected in step 2.
The Master Fader now controls the output levels
of all tracks routed to it.
4
On the Master Fader, click an Insert button
and choose one of the Digidesign Dither plug-
ins.
For more information about dither, see
“Dither” on page 660.