Logic Pro 9 User Manual - Help Library - Apple

782 Chapter 27 Mixing
When using output channel strips in this way, you cannot apply any further send effects
to the signal flow, as you would using aux channel strips. You can, however, control
settings and insert effect plug-ins using the individual controls of the output channel
strip.
Unlike aux channel strips,
output channel strips do
not have Send slots.
In some cases you might want to prevent individual output channel strips from being
controlled by the master channel strip—outputs used as send effects to external hardware
devices, for example. Simply switch such output channel strips to Solo-Safe mode by
Control-clicking their Solo button and they won’t be affected by the master channel strip.
See Soloing Channel Strips.
The Insert slots of output channel strips allow signal processing during the mastering
process, as well as during normal playback. Typical mastering tools are the compressors,
deessers, and equalizers. Due to technical reasons, you can only use plug-ins that don’t
require mono to stereo conversions. In other words, you can use stereo to stereo plug-ins
on stereo output channel strips, and mono to mono plug-ins on mono output channel
strips. Surround (or multi-mono) versions of plug-ins can be used on mono or stereo
output channel strips. Mono to multi-mono variants can be used on mono output channel
strips. Stereo to surround, stereo to multi-mono, and true surround versions of plug-ins
are accessible in stereo output channel strips.
Defining a Channel Strip’s Stereo Output
In Logic Pro you can choose the physical output pair on which the stereo output is played.
By default, it is played on Stereo Output (Output 1-2). But what if you are exchanging
projects with another studio that uses a different output pair when stereo monitoring,
for example? You can simply change the stereo output preference.