Synthesizers are typically controlled with a piano-style keyboard, in which each key functions as a switch to turn electronic circuits on and off. Although keyboards are the most common control interface, other devices such as saxophone-style wind controllers, MIDI-equipped electric guitars, drum pads or computers are used to control synthesizers. Synthesizers can produce a wide range of sounds, which can either imitate other instruments or generate unusual new timbres.

The first electric synthesizer was invented in 1876 by Elisha Gray, who is best known for his development of a telephone prototype. Robert Moog created a revolutionary synthesizer which was used by Wendy Carlos's Switched-On Bach (1968) a popular recording which introduced many musicians to the sound of synthesizers. In the 1970s, the development of miniaturized solid-state components allowed synthesizers to become self-contained, portable instruments, which made them easier to use in live performances. By the early 1980s, companies such as Yamaha began selling compact, modestly priced synthesizers such as the DX7, and MIDI (Musical Instrument Digital Interface) was developed, which made it easier to integrate and synchronize synthesizers with other electronic instruments. In the 1990's complex synthesizers no longer required specialist hardware and began to appear as software for the pc, often as hardware emulators with on-screen knobs and panels.

Operation

main: Sound synthesis

The device used to trigger musical sounds in the synthesizer is called the controller. Performers often play a synthesizer by depressing keys on a musical keyboard; however, a number of other controllers are used, including saxophone-style MIDI wind controllers and MIDI guitar synthesizer controllers. Most electronic keyboards use a keyboard matrix circuit in which the rows and columns are made up of wiring. On electric and electronic keyboards, there is an electric switch under each key. Depressing a key connects a circuit, which causes the tone generation mechanism to be triggered.

Types of synthesis

There are three main types of synthesizers: analog, digital and software. In addition, some synthesizers rely upon combinations of these three types and are known as hybrid synthesizers.

Wavetable

Wavetable synthesis uses a digital recording of an existing sound. These are known as samples, replayed at a range of pitches. Sample playback replaces the oscillator circuit found in other synthesizers. Most music workstations process sounds using effects such as filters, low-frequency oscillation, and ring modulators. Sample playback commonly replays samples at a faster speed, instead of changing the pitch. For example, to alter the frequency of a sound one octave higher, it is played at double speed; inversely, to shift the frequency of the sound one octave lower, it is played at half-speed. Instruments dedicated to recording and playing samples are known as samplers.