An electronic apparatus for generating musical sounds, usually fitted with one or more keyboards and loudspeakers. One of the earliest and best known was developed in 1964 by Robert A Moog (19342005). Like many of those which followed, it could produce only one sound at a time, but since 1975 newer polyphonic types have been developed, including digital ones based on microprocessors, which are not limited in this respect.
A synthesizer (or synthesiser) is an electronic musical instrument designed to produce electronically generated sound, using techniques such as additive, subtractive, FM, physical modelling synthesis, or phase distortion.
Synthesizers create sounds through direct manipulation of electrical voltages (as in analog synthesizers), mathematical manipulation of discrete values using computers (as in software synthesizers), or by a combination of both methods. In the final stage of the synthesizer, electrical voltages generated by the synthesizer cause vibrations in the diaphragms of loudspeakers, headphones, etc. This synthesized sound is contrasted with recording of natural sound, where the mechanical energy of a sound wave is transformed into a signal which will then be converted back to mechanical energy on playback (though sampling synthesizers significantly blur this distinction).
Synthesizers typically have a keyboard which provides the human interface to the instrument and are often thought of as keyboard instruments. However, a synthesizer's human interface does not necessarily have to be a keyboard, nor does a synthesizer strictly need to be playable by a human. (See sound module.)
The term "speech synthesizer" is also used in electronic speech processing, often in connection with vocoders.
Sound basics
When natural tonal instruments' sounds are analyzed in the frequency domain, the spectra of tonal instruments exhibit amplitude peaks at the harmonics.
Percussives and rasps usually lack harmonics, and exhibit spectra that are comprised mainly of noise shaped by the resonant frequencies of the structures that produce the sounds.
In most conventional synthesizers, for purposes of resynthesis, recordings of real instruments can be thought to be composed of several components.
These component sounds represent the acoustic responses of different parts of the instrument, the sounds produced by the instrument during different parts of a performance, or the behaviour of the instrument under different playing conditions (pitch, intensity of playing, fingering, etc.) The distinctive timbre, intonation and attack of a real instrument can therefore be created by mixing together these components in such a way as resembles the natural behaviour of the real instrument.
One of the most important parts of any sound is its amplitude envelope. Most often, this shaping of the sound's amplitude profile is realized with an "ADSR" (Attack Decay Sustain Release) envelope model applied to control oscillator volumes.
Although the oscillations in real instruments also change frequency, most instruments can be modeled well without this refinement.
Overview of popular synthesis methods
Subtractive synthesizers use a simple acoustic model that assumes an instrument can be approximated by a simple signal generator (producing sawtooth waves, square waves, etc...) followed by a filter which represents the frequency-dependent losses and resonances in the instrument body. The combination of simple modulation routings (such as pulse width modulation and oscillator sync), along with the physically unrealistic lowpass filters, is responsible for the "classic synthesizer" sound commonly associated with "analog synthesis" and often mistakenly used when referring to software synthesizers using subtractive synthesis. Although physical modeling synthesis, synthesis wherein the sound is generated according to the physics of the instrument, has superseded subtractive synthesis for accurately reproducing natural instrument timbres, the subtractive synthesis paradigm is still ubiquitous in synthesizers with most modern designs still offering low-order lowpass or bandpass filters following the oscillator stage.
One of the newest systems to evolve inside music synthesis is physical modelling.
One of the easiest synthesis systems is to record a real instrument as a digitized waveform, and then play back its recordings at different speeds to produce different tones. See also: Sample-based synthesis.
Synthesizer basics
There are two major kinds of synthesizers, analog and digital.
There are also many different kinds of synthesis methods, each applicable to both analog and digital synthesizers.
Subtractive synthesis Additive synthesis Granular synthesis Wavetable synthesis Frequency modulation synthesis Phase distortion synthesis Physical modelling synthesis Sampling Subharmonic synthesisThe start of the analogue synthesizer era
The first electric musical synthesizer was invented in 1876 by Elisha Gray , who was also an independent inventor of the telephone.
Gray accidentally discovered that he could control sound from a self vibrating electromagnetic circuit and in doing so invented a basic single note oscillator.
Other early synthesizers used technology derived from electronic analog computers, laboratory test equipment, and early electronic musical instruments. The giant Mark II Music Synthesizer, housed at the Columbia-Princeton Electronic Music Center in New York City in 1958, was only capable of producing music once it had been completely programmed. It used a paper tape sequencer punched with holes that controlled pitch sources and filters, similar to a mechanical player piano but able to generate a wide variety of sounds.
In 1958 Daphne Oram at the BBC Radiophonic Workshop produced a novel synthesizer using her "Oramics" technique, driven by drawings on a 35mm film strip.
By the 1960s, synthesizers were developed that could be played in real time but were confined to studios because of their size.
Early synthesizers were often experimental special-built devices, usually based on the concept of modularity.
Robert Moog, who had been a student of Peter Mauzey, one of the engineers of the RCA Mark II, created a revolutionary synthesizer that could actually be used by pop musicians.
Micky Dolenz of The Monkees bought one of the first three Moog synthesizers and the first commercial release to feature a Moog synthesizer was The Monkees' fourth album, Pisces, Aquarius, Capricorn & During the late 1960s, hundreds of other popular recordings used Moog synthesizer sounds. The Moog synthesizer even spawned a subculture of record producers who made novelty "Moog" recordings, depending on the odd new sounds made by their synthesizers (which were not always Moog units) to draw attention and sales.
Moog also established standards for control interfacing, with a logarithmic 1-volt-per-octave pitch control and a separate pulse triggering signal.
Other early commercial synthesizer manufacturers included ARP, who also started with modular synthesizers before producing all-in-one instruments, and British firm EMS.
In 1970, Moog designed an innovative synthesizer with a built-in keyboard and without modular design--the analog circuits were retained, but made interconnectable with switches in a simplified arrangement called "normalization".
In the 1970s miniaturized solid-state components allowed synthesizers to become self-contained, portable instruments.
The first movie to make use of synthesized music was the James Bond film "On Her Majesty's Secret Service", in 1969.
Homemade synthesizers
During the late 1970s and early 1980s, it was relatively easy to build one's own synthesizer. synthesizers
All organs (including acoustic) are based on the principle of additive or Fourier Synthesis: Several sine tones are mixed to form a more complex waveform.
Most analog synthesizers produce their sound using subtractive synthesis.
Other circuits, such as waveshapers and ring modulators, can change the tonality in non-harmonic ways or create distortion effects which are often not found in natural sound sources. In spite of the popularity of modern digital and software-based synthesizers, the purely analog modular synthesizer still has its proponents, with a number of manufacturers producing modules little different from Moog's 1964 circuit designs, as well as many newer variations like the Moogalicious 900, invented in 1998.
Microprocessor controlled and polyphonic analog synthesizers
Early analog synthesizers were always monophonic, producing only one tone at a time.
By 1976, the first true music synthesizers to offer polyphony had begun to appear, most notably in the form of Moog's Polymoog, the Yamaha CS-80 and the Oberheim Four-Voice.
When microprocessors first appeared on the scene in the early 1970s, they were expensive and difficult to apply.
The first practical polyphonic synth, and the first to use a microprocessor as a controller, was the Sequential Circuits Prophet-5 introduced in 1978.
One of the first real-time polyphonic digital music synthesizers was the Coupland Digital Music Synthesizer.
MIDI control
Synthesizers became easier to integrate and synchronize with other electronic instruments and controllers with the invention in 1983 of MIDI, a time-coded serial interface cable.
The so-called General MIDI (GM) software standard was devised in 1991 to serve as a consistent way of describing a set of over 200 tones (including percussion) available to a PC for playback of musical scores. For the first time, a given MIDI preset would consistently produce an oboe or guitar sound (etc.) on any GM-conforming device.
OSC, OpenSound Control, is a proposed replacement for MIDI which was designed for networking.
FM synthesis
FM Synthesis is when one oscillator is used to modulate another oscillator. John Chowning of Stanford University is generally considered to be the first researcher to conceive of producing musical sounds by causing one oscillator to modulate the pitch of another.
Most FM synthesizers use sine-wave oscillators (called operators) which, in order for their fundamental frequency to be sufficiently stable, are normally generated digitally (several years after Yamaha popularized this field of synthesis, they were outfitted with the ability to generate wavforms other than a sine wave). FM synthesis is fundamentally a type of additive synthesis and the filters used in subtractive synthesizers were typically not used in FM synthesizers until the mid-1990s. By cascading operators and programming their envelopes appropriately, some subtractive synthesis effects can be simulated, though the sound of a resonant analog filter is almost impossible to achieve. FM is well-suited for making sounds that subtractive synthesizers have difficulty producing, particularly non-harmonic sounds, such as bell timbres.
Chowning's patent covering FM sound synthesis was licensed to giant Japanese manufacturer Yamaha, and made millions for Stanford during the 1980s. By the time the Stanford patent ran out, almost every personal computer in the world contained an audio input-output system with a built-in 4-operator FM digital synthesizer -- a fact most PC users are not aware of.
The GS1 and GS2 had their small memory strips "programmed" by a hardware-based machine that existed only in Hamamatsu (Yamaha Japan headquarters) and Buena Park (Yamaha's U.S. headquarters). Interestingly, what became the DX7's 4-stage ADSR at that time actually had many break points....about 75 (which proved quite ineffective in modifying sounds, hence the subsequent regress to the analog-synth type ADSR envelope generators).
During the time period from 1981-1984, Yamaha built a recording studio on Los Feliz Boulevard in Los Angeles dubbed the "Yamaha R&D Studio".
The Japanese engineers in Hamamatsu failed to create more than a handful of pleasing sounds for the GS1 with the 4-monitor programming machine, although one of them was used on the recording of "Africa" by Toto. At one point, Mr. John Chowning was invited to try to assist in creating new sounds with FM Synthesis. He came to the Yamaha R&D Studio, and spent a long time trying to make the FM theory result in a useful musical sound in practice.
Thereafter, a select group of prominent studio synthesists was hired by Yamaha to try to create the voice library for the GS1 (with that same programming tool).
Between Gary and Bo (and a third programmer hired in the United Kingdom named David Bristow), they created the bulk of the voices for the GS1 and GS2 that really caught the attention of both musicians and musical instrument dealers in the Yamaha channel, through both NAMM (National Association of Music Merchants) demonstrations and in-store demonstrations.
The CE20 and CE25 "combo ensembles" were sold in the home piano/organ channel in the U.S., but they were accepted to a limited extent in the "professional" music scene.
The hardware-based FM "programmer" for the CE20/25 was a rack of breadboard electronics about the size of a telephone booth.
At one time, a young Yamaha engineer was assigned the odious task of listening to real instrument recordings, and trying to emulate them with that crude FM synthesis programmer for the CE20/25's EPROM's.
Despite his difficulties, there were a couple of notable recordings produced in the U.S. utilizing the CE20, including Al Jarreau's "Mornin'".
Despite a lot of internal pressure from product management within the Yamaha International US division, and all that was going on at the time in terms of the adoption of the MIDI standard by many other companies in the industry, it was decided that the CE20 and CE25 did not need MIDI, since they were relegated to the "home" channel.
While all of this was going on, the DX7 development team was working on what would be the most successful Yamaha professional keyboard to date at the Nippon Gakki headquarters in Hamamatsu.
They called in the Yamaha International Corporation product managers from the U.S., and held a series of critical meetings in Hamamatsu to review their design concepts.
The Nippon Gakki engineering team was headed by "Karl" Hirano. Hirano-san selected "Karl" because he liked Karl Malden (who at the time, was on the long-running television show, "Streets of San Francisco" with Michael Douglas.)
Key to their design approach during the development stage(1981-82) was that, like the CE20 and CE25, the DX7 should be a "pre-set" synth, with only factory sounds, and no programming capability. Their rationale behind this was the extreme difficulty that the Yamaha team, Bo, Gary, and others had experienced at wielding FM synthesis and the multi-operator algorithms to make good sounds.
Luckily, the American product management staff had their way: to make the DX7 (and the relatively unsuccessful DX9) completely programmable instruments. As a result, the DX7 was an unheralded success, literally hundreds of great sounds were created, and an entire industry surrounding 3rd-party sounds was spawned.
Many of the preset "General MIDI" sounds in Wintel PCs are exact-DNA clones of numerous sounds originally created by Bo, Gary, Dave Bristow, and a handful of other synthesists.
When the DX7 was finally introduced in the U.S., Bo Tomlyn, Peter Rochon (from Yamaha Canada) and other Yamaha staff went on the road to show off the product to the North American Yamaha dealer network.
But, demand was so high for the DX7 the first year of introduction that a "grey market" influx of units originally purchased in Akihabara and other electronics outlets in Tokyo and other parts of Japan, quickly developed, and that became a serious concern for Yamaha International Corporation management.
A rumor was propagated by unknown people at Yamaha (or dealers) that the Japanese units would "blow up" upon being plugged into 120V AC outlets in the U.S., and that the sounds were different from the U.S. version.
The DX7 exceeded Yamaha's wildest expectations in terms of unit sales;
The rack-mounted TX216 and TX816, although relatively powerful studio instruments at that time, were also poor sellers, due to lack of support and difficult user interface.
After the successful introduction of the DX series, Bo Tomlyn, along with Mike Malizola (the original DX-7 Yamaha product manager) and Chuck Monte (founder of Dyno-My-Piano), founded "Key Clique, Inc.", which sold thousands of ROM cartridges with new FM/DX7 sounds (programmed by Bo) to DX7 owners around the world.
The final outcome was not far afield from what the Yamaha engineers had originally been concerned about....the huge library of sounds that propagated throughout the music industry for the FM instruments were actually created by only a handful of synth programmers. In numerous interviews and case studies conducted by Yamaha product management with both retail store owners and keyboardists, it was discovered that the average DX7 purchaser hardly ever wanted...or needed...to program his or her own synthesizer voices, since it was so difficult, and because there were so many great sounds available "off the shelf".
At the time when the FM Synthesis technology was first licensed from Stanford University, just about everyone in management at both Nippon Gakki and Yamaha International in the U.S. thought that FM would be "long-gone" by the time the license ran out (about 1996).
The list of prominent musical recordings utilizing the DX7 and the myriad of other FM synthesizers that were introduced later is significant, and new compositions utilizing FM are added to the world music library all the time. Software emulation of the DX7 voice library (including many of the Key Clique sounds) exists today in a wide range of both profssional and 'pro-sumer' studio software products.
PCM synthesis
One kind of synthesizer starts with a binary digital recording of an existing sound. The sound is (by most) still processed with synthesizer effects such as filters, LFOs, ring modulators and the like.
By contrast, an instrument which primarily records and plays back samples is called a sampler.
Because of the nature of digital sound storage (sound being measured in fractions of time), anti-aliasing and interpolation techniques (among others) have to be involved to get a natural sounding waveform as end result - especially if more than one note is being played, and/or if arbitrary tone intervals are used.
PCM-sound is obtainable even with a 1-bit system, but the sound is terrible with mostly noise, as there are only two levels, on and off.
The physical modeling synthesizer
Physical modeling synthesis is the synthesis of sound by using a set of equations and algorithms to simulate a physical source of sound.
Although physical modeling was not a new concept in acoustics and synthesis, it wasn't until the development of the Karplus-Strong algorithm, the subsequent refinement and generalization of the algorithm into digital waveguide synthesis by Julius O.
Following the success of Yamaha's licensing of Stanford's FM synthesis patent, Yamaha signed a contract with Stanford University in 1989 to jointly develop digital waveguide synthesis.
The modern digital synthesizer
Most modern synthesizers are now completely digital, including those which model analog synthesis using digital techniques. Digital synthesizers use digital signal processing (DSP) techniques to make musical sounds. Some digital synthesizers now exist in the form of 'softsynth' software that synthesizes sound using conventional PC hardware.
Digital synthesizers generate a digital sample, corresponding to a sound pressure, at a given sampling frequency (typically 44100 samples per second).
To eliminate the difficult multiplication step in the envelope generation and mixing, some synthesizers perform all of the above operations in a logarithmic coding, and add the current ADSR and mix levels to the logarithmic value of the oscillator, to effectively multiply it.
Software-only synthesis
The earliest digital synthesis was performed by software synthesizers on mainframe computers using methods exactly like those described in digital synthesis, above.
Today, a variety of software is available to run on modern high-speed personal computers.
Virtual Orchestra
A digital musical instrument, or musical network, capable of simulating the sonic and behavioral characteristics of a traditional acoustic orchestra in real time. The instrument often incorporates various synthesis and sound generating techniques.
Commercial synthesizer manufacturers
Notable synthesizer manufacturers past and present include:
Access Music Alesis ARP Akai Buchla and Associates Casio Clavia Doepfer Electronic Music Studios (EMS) E-mu Ensoniq Fairlight Generalmusic Hartmann Music Kawai Korg Kurzweil Music Systems Moog Music New England Digital (NED) Novation Oberheim PAiA Electronics Palm Products GmbH (PPG) Realtime Music Solutions (RMS) Roland Corporation Sequential Circuits Technics Waldorf Music YamahaFor a more complete list see Category:Synthesizer manufacturers
Classic synthesizer designs
This is intended to be a list of classic instruments which marked a turning point in musical sound or style, potentially worth an article of their own. For more synthesizer models see Category:Synthesizers.
Alesis Andromeda (A synthesizer with modern digital control of fully analog sound producing circuitry) ARP 2600 (The Who, Stevie Wonder, Weather Report, Edgar Winter, Jean-Michel Jarre, New Order) ARP Odyssey (Ultravox and their former frontman John Foxx, Styx, Herbie Hancock) Buchla Music Box (Morton Subotnick, Suzanne Ciani) Casio CZ-101 An early low-cost digital synthesizer (Vince Clarke) Casio VL-1 More famous for it's drum beat than its synthesizer sounds. Clavia Nord Lead (God Lives Underwater, Zoot Woman, The Weathermen, Jean Michel Jarre, the first modern analog modelling synthesizer using digital circuitry to emulate analog circuits) EMS VCS3 (Roxy Music, Hawkwind, Pink Floyd, BBC Radiophonic Workshop, Brian Eno) E-mu Emulator (The Residents, Depeche Mode, Deep Purple, Genesis) Fairlight CMI (Jean-Michel Jarre, Jan Hammer, Peter Gabriel, Mike Oldfield, Pet Shop Boys, The Art of Noise, Kate Bush) Hartmann Music Neuron (Hans Zimmer, Peter Gabriel, Guns 'n Roses, Nikos Patrelakis, David Sylvian) Korg Karma Korg M1 (Bradley Joseph) Korg Triton (Bradley Joseph, Derek Sherinian} Kurzweil K2000 Synthesizer with V.A.S.T system (Jean Michel Jarre ) Lyricon First mass-produced wind synthesizer. (Michael Brecker, Tom Scott, Chuck Greenberg, Wayne Shorter) Moog modular synthesizer (Rush [pedals only], Wendy Carlos, Tomita, Tonto's Expanding Head Band, Emerson, Lake and Palmer, The Beatles,Weezer) Moog Taurus (Rush, Genesis, The Police, U2, The Rentals) Minimoog (Pink Floyd, Rush, Yes, Emerson Lake and Palmer, Stereolab, Devo, Ray Buttigieg, George Duke) NED Synclavier (Michael Jackson, Stevie Wonder, Laurie Anderson, Frank Zappa, Pat Metheny Group) Oberheim OB-Xa (Rush, Prince, Styx, Supertramp, Van Halen) PPG Wave (Rush, Depeche Mode, The Fixx, Thomas Dolby) Roland D-50 (Jean-Michel Jarre, Enya) Roland JD-800 (Bradley Joseph) Roland JP-8000 Roland Jupiter-4 (a-ha,John Foxx, Duran Duran, The Human League, Simple Minds) Roland Jupiter-8 (a-ha,Rush, Duran Duran, OMD, Huey Lewis & the News) Roland MT-32 (de-facto standard in computer game music and effects) Roland TB-303 (Techno, Acid House) Sequential Circuits Prophet 5 (Berlin, Phil Collins, The Cars, Steve Winwood) WaveFrame AudioFrame (Peter Gabriel, Stevie Wonder) Yamaha DX7 (Rush, Steve Reich, Depeche Mode, Zoot Woman, The Cure, Brian Eno, Howard Jones, Nitzer Ebb) Yamaha CS-2 Yamaha SHS-10 One of the first "keytars" from the 1980s (Showbread (band))
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