The Electro-Harmonix Stereo Polychorus has four switch-selectable modes:
A comb filter, which creates “chime” effects. In this mode you can sweep the TUNE knob manually for “custom” flanging. The Tune control will shift the effect from a high airy tone clockwise (CW) to a rich tone counterclockwise (CCW). While the Rate control has no effect in this mode, turning the TUNE control will produce a manual or “custom” flange. The Feedback control determines how much of the processed signal is mixed in or “fed back” to the input. In Filter Matrix, turning Feedback CW will “sharpen” or increase the intensity of the effect. CAUTION: In the extreme CW position the Feedback control may cause oscillation, a squealing or roaring sound. This is normal, and may be stopped by backing off the Feedback control.
A sweeping comb filter which creates a variety of modulation effects and whooshing sounds. The Rate control determines how fast the comb filter sweeps up and down through its pitch range. Turned fully CW, the frequency is about ten cycles per second. Turned fully CCW, the sweep is slow, about one cycle every ten seconds. The pitch range of the sweep is set by the combined action of the Width and Tune knobs: The Tune control sets the center frequency, and the Width control determines how far the sweep goes. Maximum Tune range is obtained by setting the Width knob fully CW. The Feedback knob also operates as in Filter Mode.
A sweeping echo for moving sounds such as “12 string guitar” and rotating speaker effects. When Chorus mode is selected, the Feedback knob determines the number of echoes: CCW for a single repeat, CW for more. The Tune control will increase the delay time of the echo as it is turned CW. The Width control maximizes the delay range of the Tune control in its CW position, and emphasizes the modulating character of the Chorus effect as it is turned more CW. The Rate control operates as in Flange. Double Track — In this mode, all controls operate as in Chorus mode, except that this is purely an echo effect and the RATE control is disengaged.
A short-delay echo for spacious “stage effects”.
When set to on, gives a smoother well rounded sound with a “liquid” sensation, if you set your unit to a very slow flange effect it is recommended to turn this off.