By Mark Phillips, Jon Chappell

After you master the techniques of playing chords and notes smoothly and cleanly on the guitar, you can turn your attention to the external processing of your sound through effects — those magical little boxes that can transform your tone from nice and neat to gnarly and nasty or any point in between. Following are four essential effects that should find a place in any electric guitarist’s arsenal.

  • Distortion: Known by various names (overdrive, fuzz, dirt, and grit), distortion is the deliberate overloading of your system’s ability to produce a clean, unaltered signal. The resulting signal is distorted from its original form but in a musically pleasing way. Most distortion devices offer several additional controls that determine the amount of distortion in the signal, its tonal color (the balance of bass, midrange, and treble frequencies), and the overall gain, or output volume, of the altered signal. Each distortion device has its own particular character or flavor.

    Get the box whose name you can associate with the type of music you’re playing, and rely on the device’s onboard controls for subtle variations or enhancements of the effect’s core sound. Many guitarists acquire more than one distortion device so that the can play a variety of rock styles convincingly. Key tracks include “Satisfaction” by the Rolling Stones and “Foxy Lady” by Jimi Hendrix.

  • Modulation: Modulation is a category of effects that includes chorus, phase shifting, and flanging as the most popular members. All three of these effects have their role, and each has enjoyed its place in the limelight in the history of recorded popular music. All make your guitar sound swirly and whooshy to varying degrees, with chorus being the most subtle, realistic (it was named for the slight detuning effect that occurs when a chorus of singers or instrumentalists try to play in unison), and versatile. In subtle applications, chorus can make your guitar sound shimmer slightly; heavier doses of chorus give the music an undulating effect. Key Tracks include “Walking on the Moon” by the Police and “Come As You Are” by Nirvana.

  • Wah wah: This effect is an onomatopoeia. When you apply a wah wah, your guitar seems to cry out wah wah, like a distressed child. In classic rock songs, the wah pedal (consisting of a hinged treadle that rocks forward and backward on a fixed base) was operated at slow to medium speeds. In the disco era, guitarists cranked their wah wahs at a much faster rate, creating more of a wahl-wacka-wacka sound. Key tracks are “All Along the Watchtower” by Jimi Hendrix and “Sweet Child o’ Mine” by Guns N’ Roses.

  • Echo (Delay): Not to be confused with reverb (an effect that creates a sense of space from a tiled room to a cathedral and that is commonly found on amplifiers), echo (or delay; the terms are used interchangeably) is an effect that creates a discrete repetition of the guitar sound and repeats it back once, twice, or multiple times, depending on the user’s settings. Echo sounds great on both rhythm and lead guitar sounds because it works well with, or in place of, reverb, to lend a sense of space. And a deep echo on a soaring solo lead guitar passage is nothing short of epic. Key tracks are “Cathedral” by Van Halen and “Another Brick in the Wall” by Pink Floyd.