Dozens of different types of effects are available for your guitar — more than you could possibly own, not to mention use all at once. The price of these individual units varies, too, with distortion boxes as cheap as $45 and digital reverbs and delays as much as $175 (or more).
To help you sort through the myriad of flavors and types of effects, following is a list of some of the most popular ones:
Distortion: This effect simulates the sound of a guitar signal driven too hard for the amplifier; the device overdrives the signal to the point that it breaks up — but in a musically pleasing way. Distortion, to a guitarist, can mean anything from a slightly fat, warm quality to a fuzzy sustain, to screaming chain-saw fuzz, as used by metal and grunge bands.
Chorus: This effect simulates the sound of many guitars playing at once, making the overall sound fatter. Increasing the speed yields a warbling or tremolo-like effect. The Police's "Every Breath You Take" exemplifies the chorus sound.
Flanger/Phase shifter: These two devices produce similar effects that create a whooshy, swirly, underwater sound, heard on early Van Halen albums and in the rhythm guitar sound of many funk songs of the '70s.
Pitch shifter: This device (also known as a harmonizer) enables you to play in harmony with yourself by splitting your signal into two paths, the original and a user-defined musical interval, such as a major 3rd (four half steps away); it also provides choruslike effects. A popular fixed-interval pitch shifter is the octave pedal, used to great effect by Jimi Hendrix, which produces a pitch one or two (or both) octaves (12 half steps) higher or lower than the original.
Digital delay: This device produces a discrete repetition of your sound, good for echoes, spacious effects, and creating rhythmically timed repeats of your notes. The analog version was a tape-echo device that actually recorded the sound on magnetic tape and played it back moments later. Tape echoes still enjoy some popularity because of their unique, vintage-sounding, tonal quality (which is inferior to the digital version in terms of exact replication of the original signal). Listen to the opening of Guns N' Roses' "Welcome to the Jungle" to hear the sound of digital delay.
Wah-wah pedal: This effects pedal is a type of frequency filter (which varies the bass and treble content of a signal) that imbues the guitar with expressive, voicelike characteristics (it actually sounds as if it's saying "wah"). You control the sound by raising and lowering a foot pedal. This device was made popular by Jimi Hendrix and was a staple of the disco-guitar sound. Eric Clapton also gave the wah a workout on "White Room" during his Cream days.
Reverb: This effect reproduces the natural echo sound produced in environments such as a large room, gymnasium, cathedral, and so on. It's usually included on amps in a limited version (often having only one control), but having it as a separate effect gives you a lot more variety and control.
Tremolo: Like reverb, tremolo was included on many amps from the '50s and '60s (such as the Fender Twin Reverb) and is now available in a pedal. Tremolo is the rapid wavering of the volume (not pitch, like vibrato) that makes your guitar sound as if you're playing it through a slowly moving electric fan. Tommy James and the Shondells' "Crimson and Clover," Green Day's "Boulevard of Broken Dreams," and Pink Floyd's "Money" feature a prominent tremolo effect.
