Synthesizer

"Synth" redirects here. For other uses, see Synth (disambiguation).

For other uses, see Synthesizer (disambiguation).

Oberheim OB12 synthesizer front panel

A synthesizer is an electronic instrument capable of producing a wide variety of sounds by generating and combining 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 sounds, which are then processed through a loudspeaker or set of headphones.

Synthesizers are most commonly equipped with a piano-style keyboard. Each key of the keyboard acts as a switch, which can be used to turn electronic circuits on and off. Although keyboards are the most common input device, other devices such as a mouthpiece, strings, guitars, drum pads or a computer can be used to control a synthesizer. Unlike other instruments, the synthesizer is capable of generating a wide range of sounds, which can either imitate other instruments or generate new sounds.

The first electric synthesizer was invented in 1876 by Elisha Gray , who is best known for his development of a telephone prototype. However, the instrument only become popular during the 1970s and 1980s, when they became easier to use and more affordable. Today, the synthesizer is widely used by many renowned music artists worldwide.

How a synthesizer works

Main article: Sound synthesis

The inside of a Yamaha SY77 synthesizer shows the various internal components.

A modern digital synthesizer uses a frequency synthesizer microprocessor component to calculate mathematical functions, which generate signals of different frequencies; these frequencies are then played through an output device such as a loudspeaker or headphones. In most conventional synthesizers, recordings of real instruments are constituted of several components. These 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 behavior of the instrument under different playing conditions (changes in pitch, intensity of playing, fingering, etc.). 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 computational power and human programming is required. Thus, most synthesizers use between one and four oscillators by default.

Types of synthesizer

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.

PCM synthesis

One kind of synthesizer starts with a binary digital recording of an existing sound. This is called a PCM sample, and it is replayed at a range of pitches. Sample playback takes the place of the oscillator found in other synthesizers. Most music workstations still process the sound with synthesizer effects such as filters, LFOs, and ring modulators. Often, the pitch of the sample isn't changed but is simply replayed at a faster speed. For example, to shift the frequency of a sound one octave higher, it is played at double speed; inversely, to shift the frequency of thes ound one octave lower, it is played at half-speed.

By contrast, an instrument that primarily records and plays back samples is called a sampler. If a sample playback instrument does not record or process samples as a synthesizer, it is a rompler.

Due to the nature of digital sound storage (or sound being measured in fractions of time), anti-aliasing and interpolation techniques must be used to achieve a natural-sounding waveform as an end result, especially if more than one note is being played, and/or if arbitrary tone intervals are used. The calculations on sample-data must be very precise (for high quality, around 64 bits), especially if various parameters are needed to create a specific sound. If too many parameters are used, excessive calculations need to be made to avoid the rounding errors of the multiple calculations taking place.

PCM sound is obtainable even with a 1-bit system, but the output will usually be of low quality. This is evident in the Microsoft Windows PC Speaker Driver, which only allows users to play a WAV file by quickly switching the simple, built-in beep speaker on and off. Since the beginning of PCM synthesis before 1970, almost all numbers of bits from 1 to 32 have been used, but today, the most common are 16 and 24-bits, sometimes reaching 32 bits for higher quality.

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. When an initial set of parameters is run through the physical simulation, the simulated sound is generated. Although physical modeling was not a new concept in acoustics and synthesis, it wasn't until the development of the Karplus-Strong algorithm and the increase in DSP power in the late 1980s that commercial implementations became feasible.

Digital synthesizer

Digital synthesizers generate a digital sample, corresponding to a sound pressure, at a given sampling frequency (typically 44100 samples per second). In the most basic case, each digital oscillator is modeled by a counter. For each sample, the counter of each oscillator is advanced by an amount that varies depending on the frequency of the oscillator. For harmonic oscillators, the counter indexes a table containing the oscillator's waveform. For random-noise oscillators, the most significant bits index a table of random numbers. The values indexed by each oscillator's counter are mixed, processed, and then sent to a digital-to-analog converter, followed by an analog amplifier.

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. To add the values in the last step of mixing, they are converted to linear values.

Some digital synthesizers now exist in the form of software synthesizers, which synthesize sound using conventional computer hardware, usually a sound card. Others use a specialized digital signal processor.

Fingerboard synthesizer

A fingerboard synthesizer is a synthesizer with a ribbon controller or other fingerboard-like user interface used to control parameters of the sound processing. A ribbon controller is similar to a touchpad. However, most ribbon controllers only register linear motion. Although it could be used to operate any sound parameter, a ribbon controller is most commonly associated with pitch control or pitch bending.

Older fingerboards used resistors with a long wire pressed to the resistive plate. Modern ribbon controllers do not contain moving parts. Instead, a finger pressed down and moved along it creates an electrical contact at some point along a pair of thin, flexible longitudinal strips whose electric potential varies from one end to the other. Different fingerboards instruments were developed like the Ondes Martenot, Hellertion, Heliophon, Trautonium, Electro-Theremin, Fingerboard-Theremin and the The Persephone.

A ribbon controller is used as an additional controller in the Yamaha CS-80, the Korg Prophecy, the Kurzweil synthesizers, Moog synthesizers and many others. Ribbon controllers can serve as a main MIDI controller instead of keyboard (Continuum).

Software synthesizer

The earliest digital synthesis was performed by software synthesizers on mainframe computers using methods exactly like those described in digital synthesis, above. Music was coded using punch cards to describe the type of instrument, note and duration. The formants of each timbre were generated as a series of sine waves, converted to fixed-point binary suitable for digital-to-analog converters, and mixed by adding and averaging. The data was written slowly to computer tape and then played back in real time to generate the music.

Today, a variety of software is available to run on modern high-speed personal computers. DSP algorithms are commonplace, and permit the creation of fairly accurate simulations of physical acoustic sources or electronic sound generators (oscillators, filters, VCAs, etc). Some commercial programs offer quite lavish and complex models of classic synthesizers--everything from the Yamaha DX7 to the original Moog modular. Other programs allow the user complete control of all aspects of digital music synthesis, at the cost of greater complexity and difficulty of use.

History

Analog synthesizers

Main article: analog synthesizers

Trautonium, 1928

The first electric synthesizer was invented in 1876 by Elisha Gray , who is best known for his development of a telephone prototype. The "Musical Telegraph" was a chance by-product of his telephone technology. Gray accidentally discovered that he could control sound from a self vibrating electromagnetic circuit and in doing so invented a basic single note oscillator. The Musical Telegraph used steel reeds whose oscillations were created and transmitted, over a telephone line, by electromagnets. Gray also built a simple loudspeaker device in later models consisting of a vibrating diaphragm in a magnetic field to make the oscillator audible.

Other early synthesizers used technology derived from electronic analog computers, laboratory test equipment, and early electronic musical instruments. Ivor Darreg created his microtonal 'Electronic Keyboard Oboe' in 1937. Another early synthesizer was the ANS synthesizer, constructed by the Russian scientist Evgeny Murzin from 1937 to 1958. Only one model was built, which is currently stored at the Lomonosov University in Moscow.

In the 1950s, RCA produced experimental devices to synthesize both voice and music. The 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. The vacuum tube system had to be manually patched to create each new type of sound. It used a paper tape sequencer punched with holes to control pitch sources and filters, similar to a mechanical player piano, but capable of generating 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 35 mm film strip. This was used for a number of years at the BBC. Hugh Le Caine, John Hanert, Raymond Scott, the composer Percy Grainger (with Burnett Cross), and others built a variety of automated electronic-music controllers during the late 1940s and 1950s.

By the 1960s, synthesizers were developed that could be played in real time but were confined to studios because of their size. These synthesizers were usually configured using a modular design, with standalone signal sources and processors being connected with patch cords or by other means, and all controlled by a common controlling device.

Early analog synthesizers were always monophonic, producing only one tone at a time. A few, such as the Moog Sonic Six, ARP Odyssey and EML 101, were capable of producing two different pitches at a time when two keys were pressed. Polyphony (multiple simultaneous tones, which enables chords), was only obtainable with electronic organ designs at first. Popular electronic keyboards combining organ circuits with synthesizer processing included the ARP Omni and Moog's Polymoog and Opus 3.

Modular synthesizers

Main article: modular synthesizer

File:Music easel2.jpg

Buchla Music Easel

Most early synthesizers were experimental modular designs. Don Buchla, Hugh Le Caine, Raymond Scott and Paul Ketoff were among the first to build such instruments, in the late 1950s and early 1960s. Buchla later produced a commercial modular synthesizer, the Buchla Music Easel.

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 be used by musicians. Moog designed the circuits used in his synthesizer while he was at Columbia-Princeton. The Moog synthesizer was first displayed at the Audio Engineering Society convention in 1964. Like the RCA Mark II, it required a lot of experience to set up the machine for a new sound, but it was smaller and more intuitive. Less like a machine and more like a musical instrument, the Moog synthesizer was at first a curiosity, but by 1968 had caused a sensation.

File:SwitchedOnBach.jpg

Cover of Switched-On Bach

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 & Jones Ltd., in 1967, which also became the first album featuring a synthesizer to hit #1 on the charts. Also among the first music performed on this synthesizer was the million-selling 1968 album Switched-On Bach by Wendy Carlos. Switched-On Bach was one of the most popular classical music recordings ever made, and the first to go Platinum. 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. This standardization allowed synthesizers from different manufacturers to operate together. Pitch control is usually performed either with an organ-style keyboard or a music sequencer, which produces a series of control voltages over a fixed time period and allows some automation of music production.

Other early commercial synthesizer manufacturers included ARP, who also started with modular synthesizers before producing all-in-one instruments, and British firm EMS.

The Minimoog was one of the most popular synthesizers ever built

Popular synthesizers

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". Though less flexible than a modular design, it made the instrument more portable and easier to use. This first pre-patched synthesizer, the Minimoog, became very popular, with over 12,000 units sold. The Minimoog also influenced the design of nearly all subsequent synthesizers, with integrated keyboard, pitch wheel and modulation wheel, and a VCO->VCF->VCA signal flow.

In the 1970s miniaturized solid-state components allowed synthesizers to become self-contained, portable instruments. They began to be used in live performances. Soon, electronic synthesizers had become a standard part of the popular-music repertoire.

The first movie to make use of synthesized music was the James Bond film On Her Majesty's Secret Service, in 1969. From that point on, a large number of movies were made with synthesized music. A few movies, like 1982's John Carpenter's "The Thing", used all synthesized music in their musical scores.

Homemade synthesizers

The Maplin 5600 synthesizer could be built from a kit

During the late 1970s and early 1980s, it was relatively easy to build one's own synthesizer. Designs were published in hobby electronics magazines (notably the Formant modular synth, an impressive DIY clone of the Moog system, published by Elektor) and complete kits were supplied by companies such as Paia in the US, and Maplin Electronics in the UK.

Modern synthesizers

By 1976, the first true music synthesizers to offer polyphony had begun to appear, most notably in the form of the Yamaha GX1, CS-50, CS-60 and Yamaha CS-80 and the Oberheim Four-Voice. These early instruments were very complex, heavy, and costly. Another feature that began to appear was the recording of knob settings in a digital memory, allowing the changing of sounds quickly.

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. For the first time, musicians had a practical polyphonic synthesizer that allowed all knob settings to be saved in computer memory and recalled by pushing a button. The Prophet-5 was also physically compact and lightweight, unlike its predecessors. This basic design paradigm became a standard among synthesizer manufacturers, slowly pushing out the more complex (and more difficult to use) modular design.

One of the first real-time polyphonic digital music synthesizers was the Coupland Digital Music Synthesizer. It was much more portable than a piano but never reached commercial production.

The Kurzweil K250, first produced in 1983, was the first polyphonic digital music synthesizer to be commercially successful. It was noted for its ability to reproduce several instruments at once, with a velocity sensitive keyboard making it indistinguishable from an acoustic grand piano. It was priced at US$ 10,000.

Since the early 1980s, most new synthesizers have been digital. Japanese manufacturers Yamaha and Casio both played a large part as manufacturers of digital synthesizers during the 1980s and 1990s. John Chowning, a professor at Stanford University, exclusively licensed his patent covering FM synthesis to Yamaha in 1975. Yamaha subsequently released their first FM synthesizers, the GS-1 and GS-2. Both were costly and heavy. Yamaha soon followed with the GS series, which used a pair of smaller, preset versions - the CE20 and CE25 Combo Ensembles. These were targeted primarily at the home organ market and featured four-octave keyboards. Yamaha's third generation of digital synthesizers became their most popular. These consisted of the DX-7 and DX-9 (1983). Both models were compact, reasonably priced, and depended on custom digital integrated circuits to produce FM tonalities. The DX-7 became indispensable to many music artists of the 1980s, and demand soon exceeded supply. The DX-7 sold over 200,000 units within three years.

After the successful introduction of the DX series, Bo Tomlyn, original DX-7 project manager Mike Malizola and Chuck Monte, founded Key Clique, Inc, which sold thousands of ROM cartridges with new FM/DX-7 sounds to DX-7 owners. This lead to the demise of the Rhodes piano during the 1980s, until its comeback in the 1990s. Yamaha later licensed its FM technology to other manufacturers. By the time the Stanford patent expired, almost every personal computer in the world contained an audio input-output system with a built-in 4-operator FM digital synthesizer.

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. As such, most patents related to the technology are owned by Stanford or Yamaha. The first commercial physical modeling synthesizer was Yamaha's VL-1 in 1994.

Analog synthesizers have also revived in popularity since the 1980s. In recent years, the two trends have sometimes been combined as analog modeling synthesizers, digital synthesizers which model analog synthesis using digital signal processing techniques. New analog instruments now also accompany the large number from the digital world.

MIDI control

Main article: Musical Instrument Digital Interface

Synthesizers became easier to integrate and synchronize with other electronic instruments and controllers with the introduction in 1983 of MIDI (Musical Instrument Digital Interface). First proposed in 1981 by Dave Smith of Sequential Circuits, the MIDI standard was developed by a consortium now known as the MIDI Manufacturers Association. MIDI is an opto-isolated serial interface and communication protocol. It provides for the transmission, from one device or instrument to another, of real-time performance data including note events, commands for the selection of instrument presets (i.e. sounds [a.k.a. programs or patches] previously stored in the instrument's memory), the control of performance-related parameters such as volume, effects levels and the like, as well as synchronization, transport control and other types of data. MIDI interfaces are now almost ubiquitous on music equipment, and commonly available on personal computers (PCs).

The 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 e.g. an oboe or guitar sound on any GM-conforming device. The Standard MIDI File (SMF) format (extension .mid) combined MIDI events with delta times - a form of time-stamping - and became a popular standard for exchange of music scores between computers. In the case of SMF playback using integrated synthesizers (as in computers and cell phones), the hardware component of the MIDI interface design is often unneeded.

OSC, OpenSound Control, is a proposed replacement for MIDI which was designed for networking. In contrast with MIDI, OSC is fast enough to allow thousands of synthesizers or computers to share music performance data over the internet in realtime.

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. They are listed with the names of performers or styles associated with them. For more synthesizer models see Category:Synthesizers.

• Alesis Andromeda (Duran Duran, Nine Inch Nails)
• ARP 2600 (The Who, Depeche Mode, Stevie Wonder, Weather Report, Edgar Winter, Jean Michel Jarre)
• ARP Odyssey (Gary Numan, Ultravox and their former frontman John Foxx, Styx, Herbie Hancock)
• Buchla Music Box (Morton Subotnick, Suzanne Ciani)
• Casio CZ-101 (Erasure, They Might Be Giants, Moby, Ore)
• Casio VL-1 (Trio)
• Clavia Nord Lead (Polysics, Nine Inch Nails, God Lives Underwater, Zoot Woman, The Weathermen, Jean Michel Jarre)
• EMS VCS3 (Roxy Music, Hawkwind, Pink Floyd, BBC Radiophonic Workshop, Brian Eno, King Crimson)
• E-mu Emulator (The Residents, Queen, Depeche Mode, Deep Purple, Genesis)
• Fairlight CMI (Thomas Dolby, Jean Michel Jarre, Jan Hammer, Peter Gabriel, Herbie Hancock, Queen, Mike Oldfield, Pet Shop Boys, Art of Noise, Kate Bush)
• Hartmann Neuron (Hans Zimmer, Peter Gabriel, Guns N' Roses, David Sylvian)
• Korg DSS-1 (Uriah Heep, Ore, Steve Winwood, Joe Zawinul)
• Korg Karma (Peter Gabriel, Jordan Rudess, Rick Wakeman)
• Korg M1 (Bradley Joseph, Queen, Pet Shop Boys, The Cure)
• Korg Triton (Bradley Joseph, Derek Sherinian}
• Korg Wavestation (Depeche Mode, Gary Numan, Genesis, Jan Hammer)
• Kurzweil K250 (Stevie Wonder, Paul Schaffer)
• Kurzweil K2000 (Jean Michel Jarre, Richard Wright, Duran Duran)
• Lyricon (Michael Brecker, Tom Scott, Chuck Greenberg, Wayne Shorter)
• Moog modular synthesizer (Wendy Carlos, Tomita, Tonto's Expanding Head Band, Emerson, Lake and Palmer)
• Moog Taurus (Rush, Genesis, The Police, U2, The Rentals)
• Minimoog (Gary Numan, Pink Floyd, Rush, Yes, Emerson Lake and Palmer, Stereolab, Devo, George Duke, Rick Wakeman, Sun Ra)
• NED Synclavier (Michael Jackson, Stevie Wonder, Laurie Anderson, Frank Zappa, Pat Metheny Group, Sean Callery)
• Oberheim OB-Xa (Gary Numan, Rush, Prince, Queen, Styx, Supertramp, Van Halen)
• PPG Wave (Rush, Depeche Mode, Gary Numan, Nine Inch Nails, The Fixx, Thomas Dolby)
• Roland D-50 (Jean Michel Jarre, Enya, Erasure, Gary Numan)
• Roland JD-800 (Bradley Joseph, Genesis, Depeche Mode, MC Hammer, Gary Numan,William Orbit)
• Roland JP-8000 (The Crystal Method, Depeche Mode, The Prodigy)
• Roland Jupiter-4 (John Foxx, Duran Duran, The Human League, Simple Minds)
• Roland Jupiter-8 (Queen, Rush, Duran Duran, OMD, Huey Lewis & the News)
• 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 (a-ha, Queen, Rush, Steve Reich, Depeche Mode, Zoot Woman, The Cure, Brian Eno, Howard Jones, Nitzer Ebb, Front 242)
• Yamaha SHS-10 (Showbread)
• Yamaha CS-80 (Vangelis)

See also

• Computer music
• Electronic keyboards
• Guitar/synthesizer
• Keytar
• List of synthesizer manufacturers
• Modular synthesizer
• Musical instrument
• Software synthesizer

References

• Gorges, Peter (2005). Programming Synthesizers, ISBN 978-3-934903-48-7.

• Schmitz, Reinhard (2005). Analog Synthesis, ISBN 978-3-934903-01-2.

• Shapiro, Peter (2000). Modulations: A History of Electronic Music: Throbbing Words on Sound, ISBN 1-891024-06-X.

External links

• Progsounds — Online Synthesizer Resource
• Synth Museum — Vintage Synth Resource
• 120 years of Electronic Music — Machines used from 1870-1990
• Principles of Sound Synthesis at Salford University