Watch the Chorus online guitar lesson by Jeff McErlain from Guitar Effects Survival Guide
Chorus pedals really made their mark in the 80’s with the likes of the Boss CE-1 and CE-2, the Electro Harmonix Small Clone and the TC Electronics Stereo Chorus. I found a nice definition of chorusing on Wikipedia: “Chorus pedals mimic the effect choirs and string orchestras produce naturally by mixing sounds with slight differences in timbre and pitch. A chorus effect splits the instrument-to-amplifier audio signal, and adds a slight delay and frequency variations or "vibrato" to part of the signal while leaving the rest unaltered.” A chorus is a modulation effect but the modulation we hear is produced by delaying the wet signal a very short duration causing the doubling effect we hear. So it is actually a time based effect. Chorus pedals can provide a nice subtle doubling effect to the guitar or an extreme “watery” effect when maximized. Famous tunes that use chorus is “Come As You Are” (1991) by Nirvana, and “Brass in Pocket” (1979) by The Pretenders. But basically almost any clean guitar sound in the 80’s had some chorus on it! Certain effects are timeless such as overdrive, reverb and delay. Other effects like chorus can evoke certain time periods such as the 80’s so that is something to keep in mind when using an effect.