Synthesizer
A synthesizer or synthesiser (often abbreviated to synth) is an electronic musical instrument that generates audio signals that may be converted to sound. Synthesizers may imitate traditional musical instruments such as piano, flute, vocals, or natural sounds such as ocean waves; or generate novel electronic timbres. They are often played with a musical keyboard, but they can be controlled via a variety of other 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. 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, such as pop, hip hop, metal, rock and dance. Contemporary classical music composers from the 20th and 21st century write compositions for synthesizer.
COMPONENTS Synthesizers generate sound through various analogue and digital technique s. Early synthesizers were analog hardware based but many modern synthesizers use a combination of DSP software and hardware or else are purely software-based (see softsynth). Digital synthesizers often emulate classic analog designs. Sound is controllable by the operator by means of circuits or virtual stages that may include: Electronic oscillators – create raw sounds with a timbre that depends upon the waveform generated. Voltagecontrolled oscillators (VCOs) and digital oscillators may be used. Harmonic additive synthesis models sounds directly from pure sine waves, somewhat in the manner of an organ, while frequency modulation and phase distortion synthesis use one oscillator to modulate another. Subtractive synthesis depends upon filtering a harmonically rich oscillator waveform. Samplebased and granular synthesis use one or more digitally recorded sounds in place of an oscillator.
Low frequency oscillator (LFO) – an oscillator of adjustable frequency that can be used to modulate the sound rhythmically, for example to create tremolo or vibrato or to control a filter's operating frequency. LFOs are used in most forms of synthesis. Voltage-controlled filter (VCF) – "shape" the sound generated by the oscillators in the frequency domain, often under the control of an envelope or LFO. These are essential to subtractive synthesis. ADSR envelopes – provide envelope modulation to "shape" the volume or harmonic content of the produced note in the time domain with the principal parameters being attack, decay, sustain and release. These are used in most forms of synthesis. ADSR control is provided by envelope generators. Voltage-controlled amplifier (VCA) – After the signal generated by one (or a mix of more) VCOs has been modified by filters and LFOs, and its waveform has been shaped (contoured) by an ADSR envelope generator, it then passes on to one or more voltage-controlled amplifiers (VCAs). A VCA is a preamp that boosts (amplifies) the electronic signal before passing it on to an external or built-in power amplifier, as well as a means to control its amplitude (volume) using an attenuator. The gain of the VCA is affected by a control voltage (CV), coming from an envelope generator, an LFO, the keyboard or some other source. Other sound processing effects units such as ring modulators and fuzz bass pedals may be encountered.
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