Assigning More Audio Outputs Than Your Hardware Supports
You can assign more outputs than your current audio hardware supports, allowing you
to open sequences with multichannel output settings on computers that don’t have
professional audio interfaces connected.
If you select an audio output that exceeds the number of output channels of your
audio interface, Final Cut Pro warns you that you will not hear tracks assigned to
unavailable outputs. However, you are still allowed to use this preset. You may want to
choose or create such a preset when:
 You want to keep your project compatible with another editing system that does
support all of the audio channels in the preset. For example, you might normally
work on a system with eight audio output channels but need to edit part of your
project on a portable computer that only has a built-in stereo output.
 You want to export multiple individual AIFF files for use in another application. For
example, you can export up to 24 individual audio files from your sequence by
choosing an audio output preset with 24 output channels.