A synthesizer (often abbreviated as synth, also spelled synthesiser) is an electronic musical instrument that generates electric signals that are converted to sound through instrument amplifiers and loudspeakers or headphones.
Synthesizers may either imitate instruments like piano, Hammond organ, flute, vocals; natural sounds like ocean waves, etc.; or generate new electronic timbres.
They are often played with a musical keyboard, but they can be controlled via a variety of other input devices, including music sequencers, instrument controllers, fingerboards, guitar synthesizers, wind controllers, and electronic drums.
Synthesizers without built-in controllers are often called sound modules, and are controlled via USB, MIDI or CV/gate using a controller device, often a MIDI keyboard or other controller. Percussion synthesizers will use something that can be played with drumsticks, mallets, or the hands.
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.
Sampler synthesizers use actual recordings of instruments loaded into the instruments memory, that can be played back by the user.
Romplers use recorded sounds that are stores and retrieved from read only memory (ROM) chips.
Other less common synthesis types (see #Sound synthesis) include subharmonic synthesis, a form of additive synthesis via subharmonics (used by mixture trautonium), and granular synthesis, sample-based synthesis based on grains of sound, generally resulting in soundscapes or clouds.
Synthesizers were first used in pop music in the 1960s.
In the 1970s, synths were used in disco, especially in the late 1970s. In the 1980s, the invention of the relatively inexpensive, mass market Yamaha DX7 synth made 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, rock and dance music. Contemporary classical music composers from the 20th and 21st century write compositions for synthesizer.