A patch contains the instrument, effects, and routing settings that control the sound of a track. When you choose a patch, those settings are applied to the currently selected track. You can try a different sound for the track by choosing a different patch, as long as the patch is compatible with the track type.
You can choose a patch in the Library when you create a track, and choose a different patch at any time while you’re working. The patches displayed in the Library depend on the track type. For example, when an audio, software instrument, or Drummer track is selected, patches for that track type are available.
Patches can include one or more channel strip settings, and can also contain routing information (auxes) and metadata (for Smart Controls and controller mapping). Patches for audio tracks can include default effects settings. Patches for software instrument tracks include an instrument plug-in as well as effects settings.
For Track Stacks, the patches available in the Library vary, depending on the Track Stack type, and which track in the Track Stack is selected. For more information, see Track Stacks and the Library.
Note: Channel strip settings also appear in the Library. If you have saved channel strip settings from a previous version of Logic Pro, they appear along with patches when the corresponding track type is selected.