Use roles to organize clips and export audio files
Final Cut Pro assigns an audio role (Dialogue, Music, or Effects) to the audio portion of all clips on import.
Role assignments make it easy to organize clips by audio type, but their most powerful benefit is the ease with which you can export separate files (called media stems) from Final Cut Pro for all dialogue, music, or effects clips. This process is often used when delivering stems to match broadcast specifications or when handing off stems for mixing or post-production.
You can use roles for the following workflows:
Reassign roles: You can view and reassign clip roles in the Timeline Index, the Browser, the Info inspector, or the Modify menu. You can also view and reassign a role for an audio component in the Info inspector (or by using the Modify menu when the clip that contains the audio component is in the Timeline). See View and reassign roles. You can also create custom roles and subroles to further organize your clips.
View and organize clips by role: In the Timeline Index, you can organize clips by role, turn roles on or off, and highlight or minimize clips for viewing in the Timeline. For example, you could easily identify all your dialogue clips and play them back in isolation from other audio clips. See View clips by role in the Timeline.
Export media stems: You can export roles as media stems in a combined, multitrack QuickTime file, or as separate audio or video files. During the export process you can assign mono, stereo, or surround output for your audio channels. See Sharing projects overview.