Apple Logic Express 9 - Manual (Page 771)

For example, you might have a main signal with the output destination set to external
speakers. At the same time, you would like to hear the signal as a separate headphone
mix, including some additional effects. To do this, you would set up two separate output
destinations for your signal, with the aux channel strips controlling the headphone mix,
including the additional effects.
To output a single channel strip to two destinations
1 Open the channel strip’s Output slot, then select the main output destination for the
mix—such as speakers.
2 Open the channel strip’s Send slot, then select the bus to send the separate signal to.
An aux channel strip is created automatically. Your chosen bus is reflected in the aux
channel strip’s Input slot.
3 Open the aux channel strip’s Output slot, then select the second output destination for
the mix—such as headphones.
Your signal flow is now routed to two separate output destinations. The main signal flow
to the speakers is heard in its “dry” state. The second signal flow—via a bus to the aux
channel strip, and output to headphones—can be modified and heard in its “wet” state.
Using Multi-Output Instruments in the Mixer
There are two reasons to use multi-output instruments in your mix: to individually process
each sound in a drum kit, for example, with different effects; to route the different virtual
instrument outputs to different outputs on your audio interface. All of this is done using
the aux channel strip.
771 Chapter 27 Mixing