An electric guitar is a type of guitar with a solid or semi-solid body that utilizes electromagnetic "pickups" to convert the vibration of the steel-cored strings into electrical current.
The current may be electrically altered to achieve various tonal effects prior to being fed into an amplifier, which produces the resultant sound.
In contrast to most stringed instruments, the solid-body electric guitar does not rely as extensively on the acoustic properties of its construction to amplify the sound produced by the vibrating strings; as such, the electric guitar does not need to be naturally loud, and its body can be virtually any shape. In fact, since all the sound produced by the amplifier comes from string vibrations detected by the electric pickups, an electric guitar that produces minimal acoustic sound will actually have maximal sustain. (Since less of the energy from the string oscillations is radiated as sound energy.)
History of the Electric Guitar
Electric guitars were originally designed by an assortment of guitar-makers, electronics buffs, and instrument manufacturers, in varying combinations. Some of the earliest electric guitars used tungsten pickups and were manufactured in the 1930s by Rickenbacker. The popularity of the electric guitar began with the Big band era, the amplified instruments being necessary to compete with the loud volumes of the large brass sections common to jazz orchestras of the thirties and forties. Initially, electric guitars consisted primarily of hollow "archtop" acoustic guitar bodies to which electromagnetic transducers had been attached.
The version of the instrument that is most well known today is the "solid body" electric guitar: a guitar made of solid wood, without resonating airspaces within it. One of the first solid body electric guitars was built by musician and inventor Les Paul in the early 1940s, working after hours in the Epiphone Guitar factory. His "log" guitar, so called because it consisted of a simple rectangular block of wood with a neck attached to it, was generally considered to be the first of its kind until recently, when research through old trade publications and with surviving luthiers and their families revealed many other prototypes, and even limited production models, that fit our modern conception of an 'electric guitar.'
At least one company, Audiovox, built and may have offered an electric solid-body as early as the mid-1930s. Rickenbacher (later spelled 'Rickenbacker') offered a solid Bakelite electric guitar beginning in 1935 that, when tested by vintage guitar researcher John Teagle, reportedly sounded quite modern and aggressive.
Gibson, like many guitar-makers, had long offered semi-acoustic guitars with pickups, but it was in 1954 that the Gibson Les Paul, the instrument that would become their trademark, was introduced to the market. In the late 1940s, electrician and amplifier maker Leo Fender, through his eponymous company, designed the Fender Telecaster. In 1954 Fender introduced the Stratocaster, or Strat, which had become by the late sixties the most widely played guitar on the market. Fender is also credited with inventing the electric bass, although solidbody electric basses had appeared elsewhere as prototypes and limited production models.
Unlike the more traditionally styled and crafted Gibson instruments, Fender's guitars and basses pioneered the modular, and hence much less expensive, method of guitar making in which the body and neck of the guitar were crafted separately, using commonly available woodworking tools, and then bolted together to form a complete guitar. Today, the design of electric guitars by most companies echoes one of the two classic designs: the Les Paul or the Stratocaster.
Types of electric guitar
Most electric guitars are fitted with six strings and are usually tuned from low to high E - A - D - G - B - E, the same as an acoustic guitar, although some modern guitarists tune their guitars lower to produce a "heavier" sound. Seven-string models exist, most of which add a low B string below the E, and were made popular by Steve Vai and others in the 1980s, and were revived by some so-called nu metal bands. There are even eight-string electric guitars, but they are extremely unusual. The first model (and probably the only one) was initially custom-created for the band Meshuggah by the Nevborn Guitars company, but is now sold to the public.
Jimmy Page, an innovator of hard rock and heavy metal music, used and made famous custom Gibson electric guitars with two necks - essentially two instruments in one. These are commonly known as double neck (or, less commonly, twin neck) guitars. The purpose is to obtain different ranges of sound from each instrument; typical combinations are six-string and four-string (guitar and bass guitar) or, more commonly, a six-string and twelve-string. Such a combination may come handy when playing ballads live, where the 12-string gives a mellower sound as accompaniment, while the 6-string may be used for a guitar solo. English progressive rock bands such as Genesis took this trend to its zenith using custom made instruments produced by the Shergold company.
Some electric guitars have a tremolo arm or whammy bar, which is a lever attached to the bridge that can slacken or elongate the strings temporarily, changing the pitch or creating a vibrato. Tremolo properly refers to a quick variation of volume, not pitch; however, the misnaming is probably too established to change. Eddie Van Halen often uses this feature to embellish his playing, as heard in Van Halen's "Eruption". Early tremolo arms tended to cause the guitar to go out of tune with extended use; an important innovator in this field was Floyd Rose, who introduced one of the first tremolos which allowed the guitar to stay in tune, even after heavy use.
Electric guitars don't work with normal microphones, but with special pickups that sense the movement of strings. Such pickups tend to also pick up the ambient electrical noises of the room, the so-called "hum", with a strong 50 Hz or 60 Hz component depending on the locale. Hum is annoying, especially when playing with distortion. For this reason, so-called "humbucker" pickups were invented. Normal pickups are single-coil; humbuckers are essentially like twin microphones arranged in such a way that electrical noise cancels itself. A similar effect may be achieved using a guitar with multiple single coil pickups with an appropriate selection of dual pickups. (See main articles on pickups and humbuckers.)
A "MIDI guitar" is an electric guitar fitted with sensors for sound and note articulation. It is used to transform string vibrations into MIDI messages to control a synthesizer or other electronic musical instrument.
Electric guitar sound and effects
An acoustic guitar's sound is largely dependent on the vibration of the guitar's body and the air within it; the sound of an electric guitar is largely dependent on an electrical signal, generated by the vibration of the strings and shaped on its path to the amplifier. By the late 1960s, it became common practice to exploit this dependence to alter the sound of the instrument. The most dramatic innovation was the generation of distortion by increasing the gain, or volume, of the preamplifier in order to clip the electronic signal. This form of distortion generates harmonics, particularly in odd multiples of the input frequency, which are considered pleasing to the ear.
Beginning in the 1960s, the tonal palette of the electric guitar was further modified by introducing an effects box in its signal path. Traditionally built in a small metal chassis with an on/off foot switch, such "stomp boxes" have become as much a part of the instrument for many electric guitarists as the electric guitar itself. Typical effects include vibrato, fuzz, wah-wah and flanging, compression/sustain, delay/echo, and phase shift. Some important innovators of this aspect of the electric guitar include guitarists Jimi Hendrix, Eddie Van Halen, Steve Jones, Jerry Garcia, David Gilmour,Yngwie J. Malmsteen, Thurston Moore and Daniel Ash, and technicians such as Roger Mayer.
By the 1980s and 1990s, digital effects became capable of replicating the analog effects used in the past. These new digital effects attempted to model the sound produced by analog effects, to varying degrees of quality. Although there are some obvious advantages to digital effects, many guitarists still use analog effects for their real or perceived quality over their digital counterparts.
Some innovations have been made recently in the design of the electric guitar. In 2002, Gibson announced the first digital guitar, which performs analog-to-digital conversion internally. The resulting digital signal is delivered over a standard Ethernet cable, eliminating cable-induced line noise. The guitar also provides independent signal processing for each individual string. Also, in 2003 amp maker Line 6 released the Variax guitar. It differs in some fundamental ways from conventional solid-body electrics. For example it uses piezo pick-ups instead of the conventional electro-magnetic ones, and has an onboard computer capable of modifying the sound of the guitar to realistically model many popular guitars.