User`s guide

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Nudging Audio Tracks
On audio tracks, you can use the Pro Tools
Nudge feature, which supports single-sam-
ple increments, to nudge the affected re-
gions to preserve phase coherency. If it is
necessary to nudge a region by a large num-
ber of samples, you may want to calculate
the equivalent value in milliseconds and
nudge the Region in millisecond incre-
ments. If the value doesn’t divide evenly,
you can switch the Nudge value back to
samples and use these smaller increments
for the remainder.
The disadvantage of using this method is
that it only works with disk tracks (not live
inputs), and the timing relationship be-
tween tracks is permanently altered, which
can affect editing.
Sample Rate and How it Affects Delay
The delay in samples caused by TDM pro-
cessing is the same regardless of the sample
rate because a sample is tied to the rate of
the sample clock for the entire system.
However, when samples are converted into
a time value (milliseconds or microsec-
onds), the sample rate (44.1 versus 48 kHz)
must be taken into account.
To convert from samples to milliseconds (and
vice-versa) use this formula:
• milliseconds = samples / sample rate (in
kHz)
• samples = milliseconds X sample rate (in
kHz)
There are 44 samples per millisecond @
44.1 kHz, and 48 samples/ms. @ 48 kHz.
✽ There are actually 44.1 samples/ms at
44.1 kHz, so Pro Tools rounds down to 44
samples/ms. One time in ten, Pro Tools
rounds off to 45 samples/ms. At 48 kHz, no
rounding occurs.
Here’s an example of how to compensate
for a delay:
Imagine that you have used a hardware in-
sert on the 888/24 I/O. According to the
guidelines given previously, the total
amount of delay introduced is:
Insert = 2 samples
888/24 I/O A/D/A = 79 samples
Total = 81 samples
If you are working at 44.1 kHz, set
Nudge/Grid to milliseconds and nudge the
region backwards (earlier in time) 2 ms (2 x
44 = 88 samples). Then set Nudge/Grid to
samples, and nudge it forward (later in
time) 7 samples for a total of 81 samples.