The EHX Frequency Analyzer adds moving harmonies to the note or chords being played. Unlike other Ring Modulators, the Frequency Analyzer has controllable high order filters that reduce cross distortions and enhance the variations. The course and fine control let the user set a single frequency that will then be both added and subtracted from the original note or chord. Blend control lets you mix the new notes with the original. This is a must have pedal, especially for techno cats. Devo had their biggest hit using the Frequency Analyzer.