Moog synthesizer

Moog synthesizer.

ARP Odyssey

ARP Odyssey.

Prophet 5

Prophet 5.

A synthesizer is an electronic sound generator (often a keyboard) capable of modifying the sound generated. No instrument has had a more dramatic impact on contemporary music.



The birth of the synthesizer dates back to the mid-1940s when Canadian physicist, composer and instrument maker, Hugh le Caine (1914–77) built the electronic sackbut, an instrument widely regarded as the first true synthesizer.


In the 1950s, RCA built the huge Mark II Music Synthesizer, using vacuum-tube electronics and a punched-paper-tape system of programming – rather like a player piano. This cumbersome beast required hours of patching and programming before it was able to produce any musical sound.


Other developments of the time included Daphne Oram's novel technique of 'Oramics', which used drawings on 35-mm film to produce sound, a system that was employed by the BBC Radiophonic Workshop for several years.


Although American inventor Donald Buchla did create a commercially available synthesizer, most instruments of the 1950s and early 1960s were, due to their vast size and complexity, confined to academic institutions and studios. The wider explosion of interest in the synthesizer was the responsibility of the man whose name became synonymous with the instrument – Robert A. Moog (1934–2005).


The Moog synthesizer

Moog (pronounced to rhyme with 'vogue') had always been interested in electronic music, having built theremins with his father throughout the 1950s. Inspired by experimental composer Herbert Deutsch, Moog designed the circuits for his first synthesizer while studying for his PhD in Engineering Physics at Cornell University, where he was a student of Peter Mauzey, an RCA engineer who had worked on the Mark II Music Synthesizer. Moog demonstrated his first synthesizer at the AES (Audio Engineering Society) convention in 1964. Like the RCA machine, Moog's synthesizer was a flexible modular design in that the instrument comprised several different sections, or modules, each with a different function, which could be patched (connected) together in different combinations. Moog's first design still required a great deal of programming time, although it was smaller, lighter and more flexible than the Mark II Music Synthesizer.


Interest in the new instrument was immediate and Moog began making modular synthesizers for experimental composers and the academic community. Widespread awareness of Moog's name came when the synthesizer features in a number of commercially successful albums. Other early synthesizer manufacturers included ARP and Peter Zinovieff's Electronic Music Studios (London) Ltd (EMS).


The Minimoog

In 1970, Robert Moog produced another ground breaking instrument, the Minimoog. Unlike previous synthesizers, the Minimoog abandoned the modular design in favor of all the electronics being built into a single keyboard unit. What was sacrificed in terms of modular flexibility was gained in ease of use and portability.


Polyphonic synthesizers

Until the mid-1970s most synthesizers were monophonic – that is to say they were only capable of producing one note at once. A few exceptions, including Moog's Sonic Six and the ARP Odyssey, were duophonic (able to play two notes at once). True polyphonic instruments, able to play chords, appeared in 1975 in the form of the Polymoog, with the equally classic Yamaha C5-80 and the Oberheim Four-Voice being released the following year.


The advent of affordable microprocessor integrated circuits enabled manufacturers to bring the advantages of digital control and memory to the synthesizer. In 1972, Sequential Circuits introduced the Prophet 5, a fully programmable, polyphonic synthesizer with digital patch memory storage, which memorized all settings.


The Digital Synthesizer

The Prophet 5 paved the way for all-digital synthesizer and in 1983 Yamaha introduced the world to FM synthesis in the form of the DX7 synthesizer in the form of the DX7 synthesizer. The DX7 also featured another development first seen in 1982 on the Sequential Circuits Prophet 600 – MIDI (Musical Instrument Digital Interface).



MIDI is an industry standard communication protocol that enables electronic musical instruments (and computer systems) to be connected to one another to exchange musical data – such as note values or program-change information. Prior to MIDI, different manufacturers each pursued their own proprietary standards. This mean that getting, for example, a Yamaha instrument to communicate with a Korg device was just about impossible. In 1981, Dave Smith of Sequential Circuits proposed the idea of a standard interface in a paper to the AES and the MIDI Specification 1.0 was published in 1983. The almost universal adoption of MIDI ensured that it became a key technology central to stage and studio, with applications beyond the purely musical, such as control of lights.


Different of synthesis

Although most synthesizers have many fundamental principles in common, there are, in fact, several different forms of synthesis technique. These include:


  • Additive: in which pure sine tones are combined to create different timbres according to principles discovered by French mathematician Joseph Fourier.

  • Subtractive: in which waveforms rich in harmonics, such as saw-tooth or square wave, produced by a VCO (voltage-controlled oscillator) are passed through filters that can strip away or accentuate certain harmonics. Most analog synthesizers employ subtractive techniques.

  • FM (Frequency Modulation): devised in the early 1970s by John Chowning at Stanford University, FM was licensed to Yamaha for use in their DX instruments. FM involves the frequency of one waveform being used to modulate (modify or influence) the frequency of another, resulting in a new, much more complex sound.

  • Granular: uses multiple layers of very short (1–50 milliseconds) waveforms called 'grains' to create 'clouds' of sound.

  • Physical modeling: uses complex mathematical equations to simulate the physical characteristics of, for example, a plucked string or a struck drumskin. Due to the huge amount of processing involved, physical modeling has only been possible in real time with the development of extremely powerful processors. The first commercially available instrument to employ physical modeling was the Yamaha VL-1 in 1994.


    Other important concepts


  • Envelopes: these refer to how aspects of a sound behave over time. For example, in terms of volume, a cymbal crash has a fast attack and a long, slow decay. Typical synthesizer envelope controls give the user control over the attack, decay, sustain, and release (ADSR) portions of sound.

  • Modulation: this simply means to modify or influence, and is a key concept in bringing expressiveness to synthesized sounds. Many different aspects of sound can be modulated. For example, the pitch of an oscillator can be modulated to produce a vibrato effect or the cut-off frequency of a filter can be modulated to create a characteristic sweeping sound. Modulation can be achieved by the player operating synthesizer controls such as the modulation wheel or by increasing pressure on an after-touch-sensitive keyboard.

  • Effect: Most modern synthesizers allow the player to further modify the sound through the application of effects such as reverberation.