Stereo Combined Panner
With the stereo combined panner, the left and right pan controls are linked and keep their relative distance if you move them. It is available for channels with a stereo input and output configuration.
To activate this panner, open the context menu for a pan control and select Stereo Combined Panner.
To set the pan independently for the left and right channels, hold down Alt/Opt and drag left or right.
To reverse the left and right channels, pan the left channel to the right and the right to the left.
The area between the pan controls changes the color to indicate that the channels are reversed.
To sum two channels, set them to the same pan position (mono).
Note that this increases the volume of the signal.
To specify the default stereo panner mode for new audio tracks, set the Default Stereo Panner Mode in the Preferences dialog (VST page).