Electronic rock (also commonly referred to as electro-rock, digital rock, or synth-rock) is the use of electronic instruments in rock music. The creation of the genre began in the 1950s and slowly progressed until the late 1960s. It was not until the invention of MIDI, enabling many electronic instruments to be able to communicate with each other and letting instruments to be played and recorded much more easily and efficiently, that electronic music and electronic rock were fully integrated into the music scene.
Experiments in tape manipulation or musique concrète, early computer music and early sampling and sound manipulation technologies paved the way for both manipulating and creating new sounds through technology. The world's first computer to play music was CSIRAC in 1950-1, designed and built by Trevor Pearcey and Maston Beard and programmed by mathematician Geoff Hill. Early electronic instruments included the theremin, which uses two metal antennas that sense the position of a player's hands and control oscillators for frequency with one hand, and amplitude (volume) to produce an eerie but difficult to manipulate sound. It was used by avant garde and classical musicians in the early twentieth century and was used on a large number of 1940s and 50s science fiction films and suspense.
Electronic musical synthesizers that could be used practically in a recording studio became available in the mid-1960s, around the same time as rock music began to emerge as a distinct musical genre. The Mellotron, an electro-mechanical, polyphonic sample-playback keyboard, which used a bank of parallel linear magnetic audio tape strips to produce a variety of sounds enjoyed popularity from the mid-1960s. The initial popularity of the Mellotron would be overtaken by the Moog synthesizer, created by Robert Moog in 1964, which produced completely electronically generated sounds which could be manipulated by pitch and frequency, allowing the "bending" of notes and considerable variety and musical virtuosity to be expressed. The early commercial Moog synthesiser was large and difficult to manipulate, but in 1970 Moog responded to its use in rock and pop music by releasing the portable Mini-moog, which was much simpler, easier to use, and proved more practical for live performance. Early synthesisers were monophonic (only able to play one note at a time), but polyphonic versions began to be produced from the mid-1970s, among the first being the Prophet-5.