Chorus (audio effect)
Chorus (or chorusing, choruser or chorused effect) is an audio effect that occurs when individual sounds with approximately the same time, and very similar pitches, converge. While similar sounds coming from multiple sources can occur naturally, as in the case of a choir or string orchestra, it can also be simulated using an electronic effects unit or signal processing device.
When the effect is produced successfully, none of the constituent sounds are perceived as being out of tune. It is characteristic of sounds with a rich, shimmering quality that would be absent if the sound came from a single source. The shimmer occurs because of beating. The effect is more apparent when listening to sounds that sustain for longer periods of time.
The chorus effect is especially easy to hear when listening to a choir or string ensemble. A choir has multiple people singing each part (alto, tenor, etc.). A string ensemble has multiple violinists and possibly multiples of other stringed instruments.
Although most acoustic instruments cannot produce a chorus effect by themselves, some instruments (particularly, chordophones with multiple courses of strings) can produce it as part of their own design. The effect can make these acoustic instruments sound fuller and louder than by using a single tone generator (b.e.: a single vibrating string or a reed). Some examples:
However, while the open strings of a standard-tuned guitar (or any single-stringed instrument like ukuleles, banjos, etc.) can't produce any chorus effect, it can also be obtained by the use of alternative tunings (such as the unisons-and-octaves-only "ostrich tuning" by Lou Reed); by playing chords or fingerings with "redundant" notes (like playing the open high E string and the same "E" note on the 5th fret of the B string); and/or by using extended techniques like bending while playing a note (like playing the 5th fret on the 2nd string and, simultaneously, playing a full-tone bending in the 7th fret on the 3rd string).
Ensembles of instruments and voices can produce a natural chorus effect, such as with a string orchestra or choir.
Examples[edit]
Some examples of the use of "obviously chorused guitar tracks" include Red Hot Chili Peppers' "Soul to Squeeze" (0:00), Fripp & Eno's "Evensong" (0:37), Nirvana's "Come As You Are" (0:00, clearest at 0:48), Mike Stern's "Swunk" (0:00), and Satellite Party's "Mr. Sunshine" (0:19, right channel).[2]. The chorus effect was also a prominent hallmark of guitarist Andy Summers ("The Police"; Tracks: "Don't Stand so Close to Me", "Walking on The Moon", "Every Breath You Take").