Apple Logic Pro 8 - Manual (Page 234)

234 Chapter 10 Working With Instruments and Effects
For computationally-intensive effects such as reverb, it’s always advisable to insert
them into an aux channel. Chorus, flanger, and delay effects should also be inserted
into an aux, if they are going to be used on more than one track.
In some cases, however, it may make musical sense to patch an effect such as a delay
or chorus, directly into the Insert slot of an individual channel. This allows you to use
precise settings, and colors, on individual elements of your mix.
The golden rule is that you should use whatever sounds right in your mix. There are no
restrictions as to where effects may be used in Logic Pro.
To send a channel signal to an aux:
1 Click on a Send slot (of an audio channel, for example), and choose a bus from the
menu.
2 Drag the Send knob to set the amount of signal that you would like to send to the aux
channel.
As you do so, the (send amount) value will be shown on the Send slot.
The send amount, when set to 100%, routes the entire signal from the audio or
instrument channel to the auxiliary destination channel (see Pre and Post information
below).
3 Insert the desired effect plug-ins, and set the required level, pan, and output settings
for the destination aux channel.