DigiDesign Pro Tools, Справочное руководство

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Chapter 14: Record Setup 263
Monitoring Latency
(Pro Tools LE)
Because Pro Tools LE uses the host processor in
your computer for all audio processing, play-
back, and recording, there is a small amount of
audio delay, or latency, in the system. This la-
tency amount is related to the H/W Buffer Size—
the larger the buffer size the greater the latency.
You can reduce the amount of monitoring la-
tency for Pro Tools LE systems by reducing the
H/W Buffer Size. However, even at the smallest
buffer size, there is still some latency. In addi-
tion, reducing the buffer size limits the number
of simultaneous audio tracks you can record
without encountering performance errors.
While there may be times when you want a
larger buffer size, such as when you have higher
track counts with more plug-ins, you’ll gener-
ally want a smaller buffer size when recording
audio that is monitored through your
Pro Tools LE system.
If you are monitoring the recording source with
an external mixer before it is routed to
Pro Tools, you will not hear any latency.
To set the Hardware Buffer Size:
1
Choose Setup > Playback Engine.
2
Choose the number of samples from the H/W
Buffer Size pop-up menu.
3
Click OK.
Zero Latency Monitoring
(Mbox 2, Mbox 2 Mini, and Mbox Only)
Mbox 2, Mbox Mini, and Mbox give you the
ability to monitor your analog input signals
while recording, without hearing any latency.
This zero-latency analog monitoring is con-
trolled by the front panel Mix knob, which you
can use to blend and adjust the ratio between
the interface’s analog input and Pro Tools play-
back. For more information, refer to your sys-
tem’s
Getting Started Guide .
Low Latency Monitoring
(Digi 002, Digi 002 Rack, and Mbox 2 Pro
Only)
Digi 002, Digi 002 Rack, and Mbox 2 Pro sys-
tems can use the Low Latency Monitoring op-
tion to record with an extremely small amount
of monitoring latency, to as many tracks as each
system supports. Only tracks with inputs set to
an audio interface (not a bus) use Low Latency
Monitoring.
To use Low Latency Monitoring:
1
Record enable audio tracks by clicking their
Record Enable buttons.
2
From the Output Path selector, assign each
track to either Output 1 or Output 2 (mono), or
both (stereo). Only tracks assigned to these out-
puts use Low Latency Monitoring.
3
Select Options > Low Latency Monitoring.
When Low Latency Monitoring is enabled, any
plug-ins and sends assigned to record-enabled
tracks (routed to Outputs 1–2) are automatically
bypassed, and must remain bypassed. Also,
these tracks do not register on meters for Master
Faders.
Computers with slower CPUs may not be
able to use the 128 buffer size without en-
countering performance errors.