Chorus

Chorus pedals mimic the "phase locking" effect produced naturally by choirs and string orchestras when sounds with very slight differences in timbre and pitch assimilate one another. A chorus effect splits the instrument-to-amplifier electrical signal, adding slight frequency variations or “vibrato” to part of the signal while leaving the rest unaltered. With extreme settings, a chorus effect can produce a "spacey" sound. A well-known usage of chorus is the lead guitar in “Come As You Are” by Nirvana.