Mixing : Mixdown : Bounce Options : Bounce Source

Bounce Source
All currently active output paths (both internal mix busses and output busses) and physical outputs as defined in the I/O Setup dialog are available as the Bounce Source.
To set the bounce source:
*
Select a bus path, output path, or physical output from the Bounce Source selector.
Bus
bounced file includes only audio routed to the selected internal mix bus path.
Output
The bounced file includes only audio routed to the selected output bus path.
Physical Output
The bounced file includes only audio from all output paths mapped to the selected physical output. This is useful when working with overlapping output paths.