Specifications

92 Chapter 10 Plug-in Enhancements
As an example: Imagine a simple song with a few bass, guitar, vocal, and drum tracks.
The bass track is played through an Audio Object that contains a plug-in that
introduces a latency of 100 ms. All guitar tracks are routed to a Bus Object that contains
several inserted plug-ins. The combined latency introduced by these plug-ins is 300
milliseconds (ms). The vocals are routed through another Bus Object that has a set of
plug-ins that introduce 150 ms of latency. The drum tracks are routed straight to the
main outputs, without being routed through any plug-ins. If latencies were not
compensated for, the drum tracks would play 300 ms ahead of the guitar tracks. The
bass track would play 200 ms ahead of the guitar track, but 100 ms behind the drums.
The vocals would play 150 ms before the guitar track, but 150 ms behind the drums
and 50 ms behind the bass. Needless to say, this isn’t ideal.
With Plug-in Delay Compensation set to All, Logic shifts the bass track forward by 100
ms, thus synchronizing the bass and drum tracks. Logic will then delay both streams in
the Output Object by 300 ms, aligning them with the guitar tracks. The Bus Object that
the vocals are streamed to is also delayed by 150 ms, aligning it with the drum and
guitar streams. The precise calculations required for each stream are handled
automatically.
Plug-in Delay Compensation Limitations
Plug-in delay compensation works seamlessly during playback and mixing. The delay
created to compensate for latency-inducing plug-ins in bus, output and auxiliary
channels can be applied to non-delayed streams before they are played back.
Instrument and audio tracks (that contain latency-inducing plug-ins) can also be
shifted forward in time before playback starts.
There are, however, some limitations if you use plug-in delay compensation with live
tracks. Shifting pre-recorded instrument and audio tracks forward in time is possible
when the audio is streaming live. So, recording while plug-in delay 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 can not be shifted forward in time.
Delaying a live stream in order to synchronize it with other delayed audio channels is
not possible. This may lead to problems should you decide to make further recordings
after setting plug-in delay compensation to All, and inserting latency-inducing plug-ins
in auxes, busses, and outputs. If Logic needs to delay streams to compensate for plug-
in latencies, you will be listening to delayed audio streams during 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 Audio
Instrument tracks live when plug-in delay compensation is set to All.