In musical terms a chorus is: A) a composition in four or more parts written for a large number of singers. B) A refrain in which an audience joins a soloist in a song. C) A repeat of the opening statement of a popular song played by the whole group. D) A solo section based on the main melody of a popular song and played by a member of the group. E) A body of singers who perform choral compositions. F) A body of vocalists and dancers who support the soloists and leading performers in operas, musical comedies, and revues.
In the technology discourse a chorus is also an effect that modifies the sound of a single instrument to simulate a group of the same instruments. The subjective effect of a real chorus is caused by the fact that each of the sounds being mixed together have different frequencies and/or timbres. The mixture becomes extremely complex as the relative phases of the signals cause partial cancellation and reinforcement over a broad frequency spectrum.
The synthetic chorus effect was first obtained by subjecting the sound to a series of very short time delays and mixing them. The delays were then modulated to increase the uncertainty of the combined pitch. This “time based” method takes quite a few delays to achieve a good, rich effect. More recently pitched based chorusing has been introduced, which is sometimes more convincing as a true chorus. These units work by splitting the signal into many frequency bands and then randomly varying the phase and amplitude of each before recombining them. Both methods are valid and can produce good results, but there is often a fundamental difference in the sound between the two.