Surround : Multichannel Tracks and Signal Routing : Multichannel Signal Routing : Mono, Multi-Mono and Multichannel Plug-Ins

Mono, Multi-Mono and Multichannel Plug-Ins
Plug-Ins can be used in mono, multi-mono, or multichannel formats.
For information about mono, stereo, and mono-in/stereo-out plug-ins, see Plug-In and Hardware Inserts.
Multi-Mono Plug-Ins
Are designed for use on stereo or greater-than-stereo multichannel tracks. Multi-mono plug-ins are useful, or required, in the following situations:
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When a plug-in does not involve multichannel correlated processing (for example, when applying EQ to select sides of a multichannel signal)
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When you need to adjust signals within the multichannel track independently
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When a multi-mono plug-in is first inserted on a multichannel track, the plug-in controls are linked. You can unlink them for independent adjustment. See Linking and Unlinking Controls on Multi-Mono Plug-Ins for more information.
Multi-mono plugs-ins can also be inserted on stereo tracks, to apply unlinked plug-ins on the left and right channels.
Multichannel Plug-Ins
Are designed for use on stereo and multichannel tracks that require correlated processing, including stereo and multichannel limiting, compression, and similar effects.