User guide

Chapter 25 Mixing 593
Using Aux Channels for External Audio Processing
You can route audio signals to external devices via the individual outputs of the audio
hardware. This allows you to change their level and pan settings, and apply plug-ins, if
you wish. This is achieved through use of the I/O plug-in.
The advantage of inserting the I/O plug-in into an aux channel, is that any effects units
(or hardware mixing consoles) integrated into the Logic Express Mixer, become
available to all track and instrument channels via sends.
Using Aux Channels as Subgroups
Aux channels can be used as subgroup channels, which control the level of several
audio channels at once. As an example, all drum tracks or all different vocal takes could
be routed to a stereo aux channel, allowing control of their overall level—while still
retaining the relative differences between the individual channels.
Simply choose the desired aux channel as the output destination for the channels you
want to include in the subgroup.
As auxes can also be routed to other auxes, several effect returns (sends) can be routed
to the same subgroup, in order to adjust the level of all effects in the mix at once. This
approach makes it much easier to handle the mixdown (particularly if automated).
To record the signal of a particular subgroup (for later use as a stereo track in the
arrangement), route the “subgroup” aux to an unused output channel, and use the
Bounce function (see “Bouncing Your Project” on page 625).
Output Channels
Output channels represent the physical audio outputs of your audio interface. These
channels are used to adjust the overall level and stereo balance (or pan position, if a
mono output channel) of all track or instrument channels routed into them. The
number of available output channels is determined by the audio interface in use.
The Insert slots of output channels allow signal processing during the mastering
process (bouncing), as well as during normal playback. Typical “mastering” tools are the
compressors, de-essers, 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 channels, and mono to mono plug-ins on
mono output channels.
Output channels also provide the Bounce button. For more information, see “Bouncing
Your Project” on page 625.