KNOWN for the watery shimmer they add to electric guitar tone, chorus effects are designed to imitate the shimmer sound of a chorus of singers trying to pitch the same note.
Chorus effects split the signal from your guitar into a ‘dry’ half and a duplicate ‘wet’ signal that has a series of short delays and pitch variations applied to it. This wobbled- up signal is then blended back in with the dry signal. Discrepancies in pitch and timing between the wet and dry signals generates a ‘comb filter’ effect: a series of harmonically ordered notches in the frequency spectrum of your guitar tone that resembles the teeth of a comb.
This filtering effect alters with the varying pitch and delay times of the wet signal, controlled by the rate and depth knobs. Chorus pedals are available in both old-school analogue and modern digital varieties. Analogue versions usually sound a touch warmer than digital choruses, employing old-style ‘bucket-brigade’ delay chips to create shimmer and wobble.
Digital versions tend to be as crisp and clean as the crease in Pat Metheny’s slacks, and many, such as Boss’s popular CE-5 Chorus Ensemble, have highly tweakable features, such as stereo outputs and low- and high-pass filters.