Panning and Balancing
The blue line, or pan control, controls how a monophonic (mono) audio of a clip is distributed between left and right stereo speakers. Changing the distribution is called panning. Redistributing the audio channels of a stereophonic (stereo) clip works the same way, but the process is called balancing. Because the processes for panning and balancing audio are so similar, the following sections use the term pan to refer to both pan and balance (unless otherwise noted).
By default, the pan control appears in the middle of the clip, indicating that the pan is centered--in other words, equally distributed between the two speakers. Dragging a control handle to the top pans the audio to the left speaker; dragging it to the bottom pans the audio to the right speaker. An expanded audio track displays a blue L and R to remind you how the line corresponds to the speakers (Figures 13, 14, and 15.)
Figure 13 At the current time (indicated by the edit line), this audio clip's pan control is centered, and plays equally from both speakers.
Figure 14 When the pan control line is positioned at the top of the expanded clip, the audio is distributed to the left speaker.
Figure 15 As the clip continues to play (and the edit line moves to the right) the pan control line slopes to the bottom of the clip, distributing the audio to the right speaker.
You can use the Paste Custom command to copy and paste pan and fade adjustments from one clip to another.
As it refers to panning audio, the term balanced means centering the audio track to play back equally in both speakers. You should be aware that the term balanced can also refer to a type of audio cable and connector.