Electronic effects allow you to produce quite a range of tones and colors. Some new combo amps have effects built into them, but most of the time nearly all of the effects you want to produce will have to be created by interposing an effects unit of some sort between the guitar and the amp. The jack plug that would normally be inserted into the amp is inserted in the “in” socket of the effects unit, and another chord connects the “out” socket of the effects unit to the amp. Most effects units are powered by nine-volt batteries, although they also have a wall-socket transformer. A transformer that's not created for the unit can hum, damage the foot pedal, or not even work. We'll look at some the most commonly used effects. Each effect has an audio track on this Book's CD with the effect sound.

Reverb

This is a natural effect that gives the impression that the sound is bouncing off walls and ceilings. Modern units allow you to program the parameters of the sound, such as the size and shape of the imaginary room. Reverb is often used to breathe life into dead sound and is perhaps the most common effect used in a recording studio.

Delay

Like reverb, delay gives the sense of sound bounced off a faraway object. You can create different effects depending on the length of the delay, which is measured in milliseconds (500 milliseconds = half a second).

Echo

When the delay is long enough that the repeated signal can be heard as a distinct sound in its own right, then you have an echo. You can control the speed of the echo and get sounds that range from the early days of 1950s rock-and-roll to the experiments of Robert Fripp or Queen's Brian May.

Phase and Flange

Phasing takes place when the same signal sounds as though it is being played back from two different sources at the same time. When the two signals are slightly out of sync — that is, when the peaks of the sound wave of one signal are overlayed on the valleys of the second signal — you get a sweeping sound called phase cancellation that sounds a little like a revolving Leslie speaker for a Hammond organ, popular in the 1970s. If the delay is more dramatic, then the sweeping sound becomes known as flanging.

Chorus

By adding variations in pitch to a delayed signal, it's possible to create the sound of a doubled signal, as if a six-string guitar has become a twelve-string, in a crude analogy.

Pitch Shifting

With pitch shifting, the signal is digitally sampled — that is, a piece of a recorded track is digitally copied and then fed into a loop to be played endlessly. Then it is replayed at a different speed, which changes the original pitch to a new pitch. Units often have a range of an octave above and an octave below the original note. If, for example, you set the unit to play sixths, then every sound that goes into the unit will be played a major sixth higher.

Distortion

The best known of all effects, distorted sound can be created in a number of different ways. The volume of the signal is boosted to the point of distortion in a preamp, and then that distorted signal is amplified by the power amp.

Compression

Often used in conjunction with other effects, compression makes the guitar notes sustain for a longer period, giving them more body, although it smoothes out the overall dynamics of a note. Listen to the comparison on Track 58 with compression off and on.

Wah-Wah

Wah-wah is a sound popularized in the 1960s and 1970s by Frank Zappa and Jimi Hendrix. A foot pedal controls a filter similar to a guitar's tone control, causing an almost vocal-like quality on occasion. The rhythm guitar sound in the original version of the movie Shaft, for instance, is a typical wah-wah funk sound.

Tremolo

Tremolo is another effect that has a dated 1950s retro sound. Solid-body guitars used to have tremolo arms that could be manually activated. Now it primarily comes in a pedal unit, and it sounds as though you're playing through a slowly moving fan. However, tremolo arms are standard equipment on Fender Stratocasters even today.

Volume Pedal

The volume pedal can be set so that you can alternate, at the dip of a switch, between playing lead guitar and rhythm guitar. The pedal instantly raises or lowers the volume of the amplifier.

Combining Effects

Effects pedals can be combined, linking them together. However, the exact sequence of effects used can change the sound, depending on whether a particular effect is placed before or after another. If you use more than one effect, it's probably worthwhile considering buying a switching foot pedal unit that will help you control which effect you want to have dominate your sound, and in what order you want the effects to be.

A modern solution to this problem has been the development of a multiple-effects pedal, which can be programmed to remember a particular sound, or sequence of sounds, and also does away with a suitcase full of effects pedals littering the floor before you like mouse traps.

A word of caution: Effects will not make you play better, or help you disguise mistakes. If you can't play well acoustically, you won't play better with a bunch of tricks loaded onto your guitar.

Choose your effects with some taste. They can date you, and they can interfere with the tracking of the guitar signal, making it seem as though you are constantly playing out of sequence — that is, with “bad” time — from the other members of the group.

Always carry a good supply of batteries if you don't have a transformer, and really practice with the effect at home before you decide to use it on a gig or recording.