Apple Logic Pro 9 - Manual (Page 1201)

There are, however, some limitations if you use plug-in latency compensation with live
tracks. Shifting prerecorded instrument and audio tracks forward in time is possible when
the audio is streaming live. So, recording while plug-in latency compensation is set to
instruments and tracks will work fine—as long as you do not try to record through
latency-inducing plug-ins: A live track cannot be shifted forward in time (as Logic Pro
can’t position live audio before it happens).
Important: Delaying a live stream, in order to synchronize it with other delayed audio
channels is not possible.
This may lead to problems if you decide to make further recordings after setting plug-in
latency compensation to All, and inserting latency-inducing plug-ins in auxes and outputs.
If Logic Pro needs to delay streams to compensate for plug-in latencies, you will be
listening to delayed audio streams while recording. As such, your recording will be late
by the number of samples that the audio streams were delayed by.
For these same reasons, you may encounter increased latency if playing software
instrument tracks live, when plug-in latency compensation is set to All. This issue can be
mitigated to some extent by using the Low Latency mode (see
Working in Low Latency
Mode ).
Dealing with Latency Issues
To avoid these potential pitfalls, you should try to complete any audio and software
instrument recording before inserting latency-inducing plug-ins. If you need to record a
software instrument or audio track after setting up a latency-inducing signal routing, the
following procedure will help you to get around any possible problems.
To record after setting up a latency-inducing signal routing
1 Switch the plug-in latency compensation setting from All to Audio and Software Instrument
Tracks in the Logic Pro > Preferences > Audio > General pane.
You can also use the Toggle Plug-in Latency Compensation: All/Audio and Instrument
Tracks key command to quickly switch compensation between All or only Audio and
Software Instrument Tracks.
The Audio and Software Instrument Tracks plug-in latency compensation method shifts
tracks that contain latency-inducing plug-ins forward in time-so any audio and instrument
tracks that contain such plug-ins will be synchronized with non-delayed tracks. There is
only one exception: Live tracks can not be shifted forward in time.
The next step is to eliminate any latency introduced by plug-ins in your recording track.
2 Bypass any latency-inducing plug-ins on the recording track by Option-clicking the
respective Insert slots.
In the Audio and Software Instrument Tracks plug-in latency compensation mode,
bypassing plug-ins eliminates the latency that they create. Latency caused by plug-ins in
audio and software instrument tracks is compensated for.
1201 Chapter 41 Working with Plug-in Latencies