The EHX Pitch Fork® features two independent pitch shifting engines with full control over each. Both will transpose your pitch up or down over a /- three octave range and detune /- 99 cents. With rock solid tracking, an organic, musical tone and extensive control, it's the ultimate harmonizer. Watch Bill Ruppert's super-informative, stellar demo of this pitch-shifting powerhouse. | Electro-Harmonix

A quick look at Transpose - Matrices | Introductory Learning