A synthesizer (or synthesiser) is an electronic instrument capable of producing a variety of sounds by generating and combining signals of different frequencies. A modern digital synthesizer uses a frequency synthesizer microprocessor component to calculate mathematical functions, which generate signals of different frequencies. There are three main types of synthesizers, which differ in operation: analog, digital and software-based. Synthesizers create electrical signals, rather than direct acoustic sounds, which are then amplified through a loudspeaker or set of headphones.
Synthesizers are typically controlled with a piano-style keyboard, in which 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. 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.
A modern digital synthesizer uses a frequency synthesizer microprocessor component to calculate mathematical functions, which generate signals of different frequencies. These frequencies are played through an output device such as a loudspeaker or set of headphones. In most conventional synthesizers, simulations of real instruments consist of several components. These sounds represent the acoustic responses of different parts of the instrument. These include the sounds produced by the instrument during different parts of a performance, or the behavior of the instrument under different playing conditions (changes in pitch, intensity of playing, fingering). The distinctive timbre, intonation, and attack of a real instrument can therefore be created by mixing these components in a way that resembles the natural behavior of the actual instrument. Nomenclature varies by synthesizer methodology and manufacturer, but the components are often referred to as oscillators or partials. A higher-fidelity reproduction of a natural instrument can be typically achieved using more oscillators, but increased computer power and human programming is required. Most synthesizers use between one and four oscillators per voice by default.
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.
