Stereo Output pop-up menu: Sets the physical output pair on which the stereo output is played.
Mirroring checkbox: Becomes available for all chosen output pairs, with the exception of Output 1–2. Deselect to have the output signal routed to the chosen output pair (Output 3–4, for example). Select the checkbox to have the output signal routed to the chosen output pair (Output 3–4, for example), as well as to the physical outputs (Output 1–2).
Surround Show as pop-up menu: Sets the surround format. The choice you make automatically updates the remaining pop-up menus in the Output pane.
Surround Initialize buttons: Choose between the default setup, the ITU (International Telecommunications Union) standard, and the WG-4 standard.
Surround speaker pop-up menus: Sets the physical output speaker for each active position in the selected surround format. Inactive speaker position output pop-up menus are dimmed.
Download the guides:
Logic Pro User Guide: PDF
Logic Pro Effects: PDF