How to tune an electric guitar.

Jimi Hendrix fender guitar

The electric guitar has become a staple in jazz, rock and pop music. Today, many of us couldn't even imagine our favorite tunes without the influences of Chuck Berry, B.B. King, Eric Clapton, Jimmy Page and countless others — and who could forget how Jimi Hendrix forever changed the American national anthem?


But before that sweet sound can come through your speakers, a fascinating technological process takes place. Electric guitars essentially transform string vibrations into electromagnetic energy. The process is quick and simple to understand, but pretty impressive for a 1931 invention.

To understand how an electric guitar works, first you need to know its various components. Let's take a closer look at one of the most popular instruments in the world.

Guitar mechanics

Solid Body

The body of an electric guitar is solid and thin, as opposed to an acoustic guitar, which is hollow and creates sound through resonance. Typically, guitars are made of wood for a warmer tonal quality, but the material isn't a critical factor in producing that electric guitar sound we know so well.

In fact, the electric guitar's inventor, George D. Beauchamp of Los Angeles, Calif., specifically wrote in the patent, "The body may be varied considerably in size, shape and construction, and may be constructed of various materials without departing from the spirit of the invention."

Beauchamp also wrote that his patent's diagrams and drawings (one of which is pictured above) show a guitar with an aluminum casing. Over the past 80 years, we've seen plastic, brass and even 3D-printed guitars.

Neck, Frets and Strings

Six metal strings run from the body across the neck and frets, the ends of which are wound around the tuning pegs. Pressing on a string at a certain fret temporarily changes its tension, producing a different frequency and note.

While an acoustic guitar can have steel or nylon strings, the magnetic properties of the metal strings on an electric guitar interact with the magnetic pickups in order to produce sound.

Bridge and Whammy Bar

The designs of electric guitars may vary, but its core parts usually serve the same purposes. These parts include the bridge, tailpiece and whammy bar.

The bridge and tailpiece anchor the strings to the body of the electric guitar, and they're parallel to the pickups. Attached to the bridge is the tremolo arm, a lever that's often referred to as the whammy bar. The whammy bar loosens and tightens multiple springs within the body of the guitar, which distorts the sound and creates a wavering effect.

Volume, Tone and Pickup Selector

The volume and tone knobs adjust how the guitar sounds. The volume knob is self-explanatory — the guitarist can make the guitar sound louder or softer — but the tone knob acts more like a filter. It interacts with a capacitor to get rid of high frequencies and extracts a fuller, warmer sound.

The pickup selector allows guitarists to get a particular sound, choosing a single pickup or a combination of pickups. The pickup closest to the bridge, where string tension is the highest, picks up higher frequencies, whereas the pickup closest to the neck, where string tension is the lowest, picks up lower frequency sounds (also known as bass).

Pickups

Pickups comprise the most important part of the electric guitar's technology. A pickup is a set of six magnets wrapped thousands of times in copper wire thinner than a human hair. Electric guitars typically have two or three pickups, and each magnet corresponds to a particular string.

The magnets in a pickup produce a stable magnetic field when the guitar is at rest. Once the guitarist strums or plucks the strings, the vibrations disturb the field and induce an electric current in the coil. This is a basic rule of physics called Faraday's Law of Induction, which states that a changing magnetic field will generate electricity.

When plucked, any given string on a guitar vibrates at a certain frequency. If you pluck the A string, for example, it will vibrate at 440 Hz, which will induce a current of the same frequency in the pickup.

This electric current is then carried to the input jack, and then through a cord to the amplifier.

The Amp

The electric guitar can't reach its full potential without the amplifier, which is often considered part of the instrument.

The current from the metal strings first passes through the preamplifier, which prepares the small electrical signal before the current reaches the amp. The preamp's main purpose is to reduce noise and interference in the electric guitar's sound and give it enough power to reach the amplifying stage.

Depending on the amp, the audio signal is sent throughout a series of vacuum tubes or digital processors, which create louder copies of the source. Once the signal is suitably conditioned and loud enough, it's sent to the amp's speaker and reaches our ears.