Apple Logic Pro 9 - Manual (Page 1179)

When a multi-channel plug-in is first inserted into a surround channel, it is automatically
preconfigured to match the channel’s surround format, and to make the best use of the
plug-in’s capabilities. For example, a plug-in with mono and stereo capabilities is inserted
into a 5.1 bus. It is preconfigured as two stereo pairs, with the addition of a mono center
and mono LFE channel. The necessary links and tabs are created automatically.
When you link channels, keep the following in mind:
• If you link two channels as a stereo pair, the left channel is always assigned as the
master.
• If one or more channels are added to an existing group, the new members adopt the
values of the group.
• If you assign several channels to an unused group, the setting of the (front) Left channel
is used for all group members.
Working with Side Chains
When inserting a side chain–capable plug-in, the side chain source (selected in the plug-in
header) is routed to all surround instances.
The detection circuits of grouped plug-in instances are linked, and react as one unit. This
ensures that the spatial surround image is not skewed or deformed.
Note: This is also true when no side chain input is selected. In this case, the group’s
combined individual inputs are used to feed the linked detection circuit—effectively
acting like a side chain source.
1179 Chapter 39 Working with Surround