WHAT SYNTHESIS MEANS
A synthesizer generates sound from scratch using electronic circuits or digital computation, rather than amplifying the acoustic vibration of a physical object (string, column of air, drum membrane). The theoretical basis for synthesis was established by Hermann von Helmholtz in On the Sensations of Tone (1863): his demonstration, building on Fourier's theorem, that complex tones are the sum of multiple sine waves (additive synthesis), means that any sound can in principle be created by combining enough sine waves at appropriate frequencies and amplitudes. This insight - that all timbre is ultimately a matter of spectral composition - is the foundation of every synthesis technique that followed.
EARLY INSTRUMENTS: FROM THEREMIN TO ONDES MARTENOT
Leon Theremin's theremin (1920) was the first electronic instrument to reach wide public awareness: the player controls pitch by moving one hand near a vertical antenna (closer raises pitch) and volume by moving the other near a horizontal loop antenna. Its ghostly, continuous tone - produced by heterodyning two oscillators - has made it the instrument of horror film scores and science fiction. The French ondes Martenot (1928), developed by Maurice Martenot, uses similar electronics but adds a keyboard and a ribbon controller for portamento effects; Olivier Messiaen scored for it regularly, giving it a place in the serious concert repertoire.
ROBERT MOOG AND THE VOLTAGE-CONTROLLED SYNTHESIZER
Robert Moog's development of the voltage-controlled synthesizer in 1964 - specifically his invention of the transistor ladder filter (the Moog filter, US patent 3475623) - was the technical breakthrough that made musical synthesis practical. Voltage control meant that the synthesizer's parameters could be modulated in real time by other electronic signals, allowing complex sounds to evolve dynamically. The architecture of a Moog-type subtractive synthesizer defines the vocabulary of analog synthesis: the VCO (Voltage Controlled Oscillator, generating the raw waveform - sawtooth, square, triangle, sine), the VCF (Voltage Controlled Filter, shaping the frequency content - typically a low-pass filter that removes high harmonics), the VCA (Voltage Controlled Amplifier, controlling volume), the ADSR envelope generator (controlling how a sound begins: Attack time, Decay time to sustain level, Sustain level, and Release time after key release), and the LFO (Low Frequency Oscillator, modulating other parameters at sub-audio rates to produce vibrato, tremolo, and rhythmic effects).
Wendy Carlos's Switched-On Bach (1968) - demonstrating Bach's keyboard works performed on a Moog synthesizer with meticulous attention to counterpoint, phrasing, and expressive dynamics - sold over a million copies and won three Grammy Awards. It was the cultural event that established the synthesizer as a legitimate musical instrument capable of serious artistic expression.
FROM MINIMOOG TO DX7: THE COMMERCIAL SYNTHESIZER
The Minimoog (1970) - a simplified, portable version of the Moog modular without patch cables - was the first synthesizer designed as a touring musician's instrument. Its three-oscillator architecture and the Moog filter's characteristic 'fat' sound defined keyboard texture in rock and jazz-rock fusion throughout the 1970s. Keith Emerson, Jan Hammer, and Rick Wakeman exploited its range exhaustively.
The Yamaha DX7 (1983) introduced FM synthesis (frequency modulation synthesis, developed by John Chowning at Stanford University in the 1970s) to the mass market. FM synthesis uses one oscillator (the modulator) to vary the frequency of another (the carrier), producing complex metallic, bell-like, and glassy tones unavailable in subtractive synthesis. The DX7 sold approximately 200,000 units, making it one of the best-selling synthesizers in history; its electric piano preset became the defining sound of 1980s pop and R&B.
The Roland TR-808 drum machine (1980), considered a commercial failure on release (its sounds were considered unrealistic), was bought cheaply by hip-hop and electro producers who discovered that its elastic bass drum - far more resonant than any acoustic drum - was perfectly suited to the physical demands of dance floor sound systems. Its 808 bass drum is one of the most-used sounds in contemporary music. Mark Vail, in Vintage Synthesizers (Miller Freeman, 1993), documents these instruments' histories exhaustively. Gordon Reid's Synth Secrets series in Sound On Sound magazine provides the most rigorous technical analysis of synthesis techniques available to a general audience.
SOFTWARE SYNTHESIS AND THE HARDWARE REVIVAL
VST (Virtual Studio Technology) plugins and software synthesizers - from Native Instruments' Massive and Serum (Xfer Records) to the faithful emulations of classic hardware - have made the full range of synthesis techniques available to anyone with a computer. The result is simultaneously democratizing (anyone can produce professional electronic music) and homogenizing (everyone has access to the same sounds). The current hardware modular synthesis revival - musicians investing thousands in patch cable ecosystems - represents a deliberate embrace of physical interaction, unpredictable behavior, and the specific sonic character of analog circuits that digital emulation has not fully replicated.