BFS-1 is a free frequency shifter VST plugin developed by WOK. Compatible OS(s): Windows.
BFS-1, a virtual recreation of the Bode Frequency Shifter.
Different from a pitch shifter, a frequency shifter moves all frequencies/harmonics by adding a fixed amount. The sound is similar to a ring modulator but it is possible to get the upshifted and downshifted signal separately. Unlike a ring modulator, the frequency shifter is also capable of changing the signal by a low amount, e.g. 1 Hz, to obtain effects known as “Barberpole flanging”.
This plug-in has some additional features like feedback delays in the shifting sections, an LFO (all host synced), an envelope with MIDI trigger and an envelope follower to modulate shift and/or volume.
http://www.wokwave.com