LinPlug Spectral - Manual (Page 68)

Flanger
The Spectral’s Flanger can be used to create the classic flange effect
produced by using two analog tape machines playing back the same signal
but with small (and changing) differences in the playback speed of the
machines.
The Time control defines the length of the delay line, representing the delay
between the original (tape machine 1) and the delayed / wet signal (tape
machine 2).
The Feedback control feeds the processed signal back to the input of the
effect producing a more pronounced and richer effect.
The Invert control inverts the processed signal's phase against the original
signal, giving a subtly different sound.
The Stereo dial allows adjustment of the stereo width of the Flanger. This is
effectively phase shifting the modulation on the left and right audio channel,
so often a rather smaller value is more pleasing that a fully right setting.
The Mod Rate control sets the speed of the flange effect (the speed of the
cyclic changes of the two tape machines). This setting can be either made
with the dial or set as a fraction of the song tempo using the “Sync” popup
menu.
The Mod Depth control is the key parameter for determining the depth of
the flange. The higher the setting, the more pronounced the effect.
The Pan Depth control allows the stereo position of the flanged signal to be
modulated according to the setting of the Rate parameter.