A goniometer helps you to judge the coherence of the stereo image and determine phase differences between the left and right channels. Phase problems are easily spotted as trace cancelations along the center line (M—mid/mono).
The idea of the goniometer was born with the advent of early two-channel oscilloscopes. To use such devices as goniometers, users would connect the left and the right stereo channels to the X and Y inputs, while rotating the display by 45° to produce a useful visualization of the signal stereo phase.
The signal trace slowly fades to black, imitating the retro glow of the tubes found in older goniometers, while also enhancing the readability of the display.
Goniometer button: Switch the main display to Goniometer mode.
Auto Gain knob and field: Set the amount of display compensation for low input levels. You can set Auto Gain levels in 10% increments or set it to off.
Note: To avoid confusion with the Auto Gain parameter found in other included effects and processors (such as the compressors), Auto Gain is only used as a display parameter in the meters. It increases display levels to enhance readability. It does not change the actual audio levels.
Decay knob and field: Determine the time it takes for the Goniometer trace to fade to black.