Specifications

Pro Tools Reference Guide430
Low Latency Monitoring During
Recording
For recording, Pro Tools automatically suspends
delay compensation to provide a low-latency
monitor path through the main outputs of the
record-enabled tracks. When an audio track is
TrackInput-enabled, armed for recording (in
stop), or punched in, the track’s delay compen-
sation is automatically suspended (and the
Track Compensation indicator displays 0).
Delay compensation can be intentionally ap-
plied to audio tracks regardless of input mode.
To apply delay compensation to automatically
bypassed tracks:
■ Start-Control-click (Windows) or Command-
Control-click (Macintosh) the Track Compensa-
tion indicator. Track delay will be applied to the
track and the Track Compensation Indicator
will display in blue.
Track Compensation on Auxiliary Inputs
Delay compensation on Auxiliary Inputs can be
bypassed to let you monitor outside sources
(such as the audio tracks of a slaved video deck)
with minimal latency, while still reporting the
track’s delay.
To bypass an Auxiliary Input’s delay
compensation:
Start-Control-click (Windows) or Command-
Control-click (Macintosh) the Track Compensa-
tion indicator. The reported track delay will be
zero, and will appear greyed out.
Dither
Dither is a special form of randomized noise
used to mask quantization noise in digital audio
systems. Digital audio’s poorest distortion per-
formance exists at the lowest end of the dy-
namic range, where quantization distortion can
occur. Dither reduces quantizing errors by intro-
ducing very low-level random noise, thereby
minimizing distortion artifacts as audio reaches
low level. With dither there is a trade-off be-
tween signal-to-noise performance and less-ap-
parent distortion. Proper use of dither lets you
squeeze better subjective performance out of a
16-bit data format (such as Red Book compact
discs).
Pro Tools TDM systems process all audio inter-
nally at 24-bit, and Pro Tools LE processes inter-
nally at 32-bit, floating. Without Dither to pro-
cess the 24-bit data to 16-bit, the extra 8 bits are
truncated (dropped entirely) when written to
media or a device with a 16-bit maximum (such
as CD recorders, and many DAT machines).
Dithering, on the other hand, preserves low-
level (quiet) fidelity in a surprising way—by
adding a small amount of noise to a signal.
Dither in Pro Tools
There are several dither options provided in
Pro Tools. Each has a specific application within
the various operations that could benefit from
dithering.
In addition to the TDM, RTAS and AudioSuite
dither plug-ins, Pro Tools has a built-in dither
capability.