Backbone of the electronic music, the synthesizer is an electrical instrument that creates, or "synthesizes" audio by processing an electrical current or digital values. Originally pioneered in the 1960's by Moog Music, Buchla, Oberheim, Dave Smith and so many others, they usually synthesize sound by processing audio created by oscillators into filters, envelopes and low-frequency oscillators (LFOs). Later in the 1980's, Yamaha introduced digital synthesizers and a new type of synthesis which revolutionized pop music. In parallel, companies like Doepfer developped modular synthesis, expanding the genre of electronic music.