iZotope Mobius Filter - Filter Sweep Plug-In (Educational, Download)

Mobius Filter from iZotope is a plug-in based on the Shepard Tone, which produces the illusion of an infinitely ascending or descending filter sweep. The effect can add motion to otherwise static material without obscuring the underlying frequency content of the source audio, create massive filter swells, mind altering alternatives to flange effects, or provide fresh inspiration for exploratory soundscapes.