An effect which adds a sense of spaciousness and "fullness" to a sound, as if it were being performed by a number of identical instruments playing in unison. It is a particularly useful effect on synthesizer outputs; many of the early polyphonic synths of the 1975-1985 time period included built-in chorus circuits (which helped improve the somewhat weedy sound of some of these synths). On bass sounds, chorusing dramatically alters the timbre, creating an effect as if the same sound were being played in two or three octave intervals above the input sound.