About audio channels and audio components
Audio files can contain a single audio channel or multiple audio channels. Channels usually correspond to microphone inputs during recording or to speakers for multichannel output. For example, a stereo audio file usually contains left and right channels that match what you hear from the left and right speakers during playback.
Final Cut Pro automatically groups channels into audio components according to how the channels are configured for the clip. You can expand the audio portion of clips to view and edit audio components down to the individual channel level. You can then make separate volume or pan adjustments or apply and keyframe different audio effects for each component. For more information, see Audio editing overview.
The number of audio components you see corresponds to the number of channels you’ve configured in your source clip.
Note: Many popular digital audio file formats, such as AAC and MP3, use interleaved stereo files, which do not contain separate left and right channels. A stereo clip with interleaved left and right channels appears as a single audio component in the Audio inspector and the Timeline. If you change the clip’s channel configuration from Stereo to Dual Mono, the channels appear as two separate audio components.
For more information, see Configure audio channels.