Acoustic guitars and their various musical relatives can be traced back thousands of years, but the idea of a guitar using electric currents to amplify its sound had to wait until the 1930s to start to take root. Necessity was, perhaps, the mother of invention here, as the volume of the guitar, used previously in blues and jazz, could not compete with the new sounds of the big band and the shriek of brass instruments. Early experiments with simply adding microphones to guitars had only limited success, partly due to the quality of the tone and partly because of the feedback that could occur as soon as a reasonable volume was reached. The breakthrough came when Les Paul, a jazz guitarist, successfully experimented with a magnetic pickup system that could convert the vibrations of the strings to an electrical signal to be amplified and sent to a speaker. Soon, guitarists started adding pickups to their hollow-bodied guitars, but in fact there was no need for an electric guitar to have a hollow body, as the pickups could detect very subtle vibrations and amplify them anyway. Before long, Fender, Rickenbacker and, of course, Gibson were producing solid-bodied electric guitars.
Innovations unique to the electric guitar
Electric guitars allowed many innovations that would go on to define their sound. Most noticeably was the fact that volume and tone controls could be added to the electronics between the pickup and the cable, which meant that the accomplished guitarist could adjust the tone and loudness whilst on stage. Second and third pickups were added at various points along the body to take advantage of the difference in tone at various points along the strings, and these could be blended together with multiple controls. The tremolo arm appeared, allowing notes to be bent down or up (before, they could only be bent upwards by pulling the string away from its natural line, thus tightening it). The tremolo arm was part of the early sound of rock ?n? roll, and could make a vibrato sound or create the long, sustained, wailing sounds associated with Jimi Hendrix. Other sound effects, such as chorus, overdrive, vibrate, wah-wah, reverb and delay (echo) could also be controlled via foot pedals by the player, further adding to the variety of sounds available. The pickup was also applied to bass guitars, and is now seen on violins, mandolins, cellos and many other types of string instrument.
Musical styles using electric guitars
The genres of music that use electric guitars are too numerous for this article, but their origins can be traced back to the jazz and big band sound that became popular between the wars. Blues guitarists pioneered the ?dirty? sound that would later morph into heavy metal, and no rock and roll group would be complete without at least one electric guitar. Bob Dylan was once called ?Judas? by a heckler when he swapped his acoustic for an electric on stage, a significant moment in electric folk. The sixties saw mainstream pop and psychedelic bands putting the instrument to good use, and disco, punk, ska and reggae music of the seventies used the instrument?s inherent rhythm; a lively and thriving African sound is once of the guitar?s most innovative current streams. Whenever a new technology has come along, especially the electronic revolution of the late 1970s and 1980s, people have written off the electric guitar, but it shows no sign of losing popularity.