Synthesizers use various methods to generate electronic signals (sounds). Among the most popular waveform synthesis techniques are subtractive synthesis, additive synthesis, wavetable synthesis, frequency modulation synthesis, phase distortion synthesis, physical modeling synthesis and sample-based synthesis.
Synthesizers were first used in pop music in the 1960s. In the late 1970s, synths were used in progressive rock, pop and disco. In the 1980s, the invention of the relatively inexpensive Yamaha DX7 synth made digital synthesizers widely available. 1980s pop and dance music often made heavy use of synthesizers. In the 2010s, synthesizers are used in many genres of pop, heavy metal, rock and dance music. Contemporary classical music composers from the 20th and 21st century write compositions for synthesizer.
One of the earliest electric musical instruments, the Musical Telegraph, was invented in 1876 by American electrical engineer Elisha Gray. He accidentally discovered the sound generation from a self-vibrating electromechanical circuit, and invented a basic single-note oscillator. This instrument used steel reeds with oscillations created by electromagnets transmitted over a telegraph line. Gray also built a simple loudspeaker device into later models, consisting of a vibrating diaphragm in a magnetic field, to make the oscillator audible. This instrument was a remote electromechanical musical instrument that used telegraphy and electric buzzers that generated fixed timbre sound. Though it lacked an arbitrary sound-synthesis function, some have erroneously called it the first synthesizer.
In 1897, Thaddeus Cahill invented the Telharmonium, which was capable of additive synthesis. Cahill's business was unsuccessful for various reasons, but similar and more compact instruments were subsequently developed, such as electronic and tonewheel organs including the Hammond organ, which was invented in 1934.