An electronic device designed specifically to produce music, and containing certain signal processing functions and design concepts. The advent of the synthesizer, and musical electronics associated with it, has produced a new category of music, known as electronic music; it has over time revolutionized the music industry, the production of music, and to an extent the very concept of what music is.

What Is a Synthesizer? Edit

Not all electronic music instruments are considered synthesizers per se. Over the 20th century, mostly prior to 1960, various instruments were developed that produced music by electronic means. Some, although novel at the time, were timbrally limited compared to the modern synthesizer, and are not usually thought of as synthesizers today. Examples of this category include the Ondes Martenot, the Mellotron, and the Hammond organ.

The "proper" synthesizer, as first developed in the 1960s, implements two significant principles: subtractive synthesis, and voltage control. These were technologies that were practical to implement using 1960s analog circuit technology. (Digital computers were not really well enough developed at the time; there were a few attempts at digital synthesis in this era, but the technology was so expensive that it was only affordable to a few institutions.) Subtractive synthesis provides a wide variety of timbral possibilities with a relatively small number of functions; the classic signal chain for subtractive synthesis consists of an oscillator which produces a selection of harmonic-rich waveforms; a filter by which harmonics can be selectively removed, and a variable-gain amplifier which shapes the dynamics (referred to as the envelope) of each played note.

The technique of voltage control, developed independently by Bob Moog and Don Buchla in the early '60s, greatly expands the synthesis possibilities by making it possible for the output of one function to control another function. Moog and Buchla developed voltage controlled oscillators (VCO), whose frequency can be controlled by an input voltage; this allowed, for example, vibrato to be implemented by inputting the output of an oscillator running at a low frequency to the VCO. They developed voltage controlled filters (VCF), whose cutoff frequency is voltage controllable, and voltage controlled amplifiers (VCA), whose gain is voltage controllable. They also developed two devices specifically designed to produce control signals to control other functions. The low frequency oscillator (LFO) is designed to produce accurate signal waveforms at very low frequencies, typically from the lowest audio frequencies (around 20 Hz) to well below 1 Hz. It can be used to produce vibrato by controlling a VCO, or tremolo by controlling a VCA. The envelope generator, when activated by a trigger or gate signal, produces a signal that rises from (usually) zero volts to a maximum voltage in a manner that is controllable, and then returns to zero volts after some period of time. This is most commonly used to control a VCA; it "shapes" the dynamics of a note (and ensures that the note quits sounding eventually!), but it can also be used to control other things, for example, producing timbral variations by controlling a VCF.

Other methods of synthesis are certainly possible, and these may not necessarily rely on the same functions as described above. Most of these are difficult to do with analog circuitry and so are most commonly implemented in the digital domain. The advent of relatively powerful, inexpensive personal computers starting in the late 1990s led to the development of soft synths, software programs that run on a personal computer and perform synthesis functions. Although there are no voltage signals in software, many of these maintain the basic principle of voltage control, in which the output of one function can control another function.

History Edit

1900 to 1940: Precursors Edit

The earliest known electronic music instrument is the Telharmonium, constructed by Thaddeus Cahill around 1900. This consisted of banks of generators geared to run at different speeds so as to produce signals of different frequencies. A complex switching arrangement tied to an organ-like keyboard allowed the performer to play notes with selected timbral qualities, implementing a synthesis method known as additive synthesis. The whole arrangement was unwieldy (all the machinery filled six railroad boxcars) and expensive, and it lacked a good way to either transmit or record the music produced. The Telharmonium was not successful; its music was not popular and the three units built have all been scrapped. Nor do any known recordings survive.

The invention of the triode tube, and subsequent developments, enabled the basic oscillator circuitry to be made far smaller than Cahill's banks of generators. The Theremin, invented in 1920, was the first popular electronic music instrument, consisting of a single oscillator and amplifier, which the performer controlled by moving his/her hands around antenna rods projecting from the instrument; changes in capacitance in the circuitry caused by the performer's movements enabled the performer to control frequency and amplitude. The theremin briefly caused a sensation, but the very limited timbres (the basic theremin had no timbral adjustments or parameters at all) resulted in the fad dying out after a time.

Maurice Martenot developed the Ondes Martenot in 1928. This instrument expanded on the timbral and performance capabilities of the theremin. Versions of it contained a selection of different types of oscillators generating different waveforms, which could be blended for timbral variation. Further possibilities were provided via a selection of unusual loudspeaker enclosures, some containing mechanically resonant elements, which in effect performed formant filtering.

Laurens Hammond developed the first Hammond organ in 1934. This was in effect a miniaturized version of the Telharmonium; a number of small gears spun on shafts powered by a synchronous motor. Magnetic pickups at the edges of the gears picked up the waveforms, which were determined by the number and shape of gear teeth. Like the Telharmonium, this was in effect a primitive additive-synthesis machine. Like a pipe organ, notes were "on" and "off"; there was no envelope shaping capability. The Hammond was the first electronic (actually electromechanical, but the electronics were an essential component) music instrument to achieve widespread sales, and the tonewheel design remained in production until the 1970s, when it was replaced by fully electronic designs.

Hammond was also responsible for the development of what some consider the first "proper" synthesizer, which they called the Novachord. It was indeed almost a synthesizer; it had a sort of VCA and envelope generator, although it did not have a VCF. A set of top octave division oscillators produced a tone for each key on the keyboard, and each key had its VCA and envelope capability. A set of adjustable (but not voltage controlled) filters processed the mix of all notes played, in a paraphonic setup. It was a rather expensive and maintenance-intensive instrument, containing over 100 vacuum tubes (a typical radio of the era contained between 5 and 8 tubes). The Novachord had the misfortune of hitting the market just prior to the start of World War II; nonetheless, Hammond built and sold hundreds before wartime demands ended production.

1946-1960: Closing In on the Solution Edit

A greater understanding of electronics (gained by necessity during the war), plus the advent of the first electronic recording means, led to many advances in the period shortly after the war. A device called the "analog computer" had been greatly improved during the war for various war uses (mainly gun aiming and targeting), paced by the development of the operational amplifier -- an essential component of most practical analog circuits. Analog computers after the war were used for a variety of purposes, from predicting the movement of groundwater to simulating nuclear explosions. An analog computer contains many of the same basic circuits and functions as an analog synthesizer, and some performers today seek out vintage analog computers to use as musical instruments.

The explosive growth of both industrial and consumer electronics after the war led to a booming market for the test instruments needed by the people who developed and repaired such electronics. Devices such as lab oscillators, filters, and function generators became available inexpensively thanks to mass production. Experimenters soon discovered that they could record signals from these devices on magnetic recording tape at various speeds, cut the tapes into pieces, and then edit pieces back together in a chosen order to produce melodies. They also discovered that they could record other things -- found objects, environmental sounds, conventional instruments, etc -- process those through the electronics, and cut and reassemble those tapes too. The process soon got a name: the tape studio, and it was the first electronic music technique used to produce both popular and "serious" music. A significant entity in this field was the BBC Radiophonic Workshop, which opened in 1958 and produced many notable pieces of theme music for BBC productions.

Probably the first instrument to actually be called a "synthesizer" was the RCA Synthesizer, developed by RCA's David Sarnoff Labs, with the first example being installed in the Sarnoff Research Center in 1955. This was the first instrument to have all of the features associated with analog synthesizers today. It was programmed with patch cords and controlled via a punched paper tape, which the performer prepared in advance. The tape specified all of the parameter values for each note played.

Moog, Buchla, Pearlman and Zinovieff Edit

In the early 1960s, an inventor and Columbia graduate in New York named Robert Moog had a small business building theremins, amplifiers, and other electronics. He conceived of a more versatile music synthesis system using analog computer components, and quickly realized that if the output of one function could control another function, the range of timbral possibilities opened up considerably. Meanwhile, on the Wet Coast of the U.S., a polymath and sometime performer with various tape-studio music ensembles around the San Francisco Bay Area named Donald Buchla had reached the same conclusion. Both set about developing functions that could be voltage controlled -- the first VCOs, VCFs, and VCAs. Both patterned the construction of their synthesizers around the way that analog computers of the era were packaged, where each function was built as an individual module, which the user could purchase and arrange in a frame in a mix-and-match configuration according to need. Thus, the first synthesizers with voltage control were modular synthesizers.

Moog and Buchla soon formed companies, R.A. Moog Inc, and Buchla and Associates respectively, with their first products appearing around 1965. Growth was slow until Wendy Carlos executed her first album of electronically performed classical music, Switched-on Bach, which was both a critical and popular success. This led to an explosion in orders, of which neither company could keep up with. Al Pearlman had been a pioneer in analog computers and operational amplifiers, and was flush with cash from having just sold a successful integrated-circuit company. Going back to his first love, which was much, he founded ARP Instruments and jumped into the synthesizer market. The company was an instant success, and soon "ARP vs. Moog" was a "religious war" between aficionados of the two companies. Meanwhile, in London, Russian expat Peter Zinovieff was working with some of the BBC Radiophonic Workshop performers to develop their own synths, and the result was the EMS company, which quickly dominated the market in the UK.

A question at the beginning that Moog and Buchla wrestled with was how the performer should actually interact with and play the instrument. Buchla had developed a range of touch sense devices and ribbon controllers which suited the purposes of the West Coast experimental musicians who were his target market. Moog and his associate Herb Deutsch, however, were looking for something more acceptable to musicians who were accustomed to conventional instruments; they envisioned marketing to the large community of jazz musicians in New York. They came up with the idea of taking a keyboard mechanism from an electric organ and wiring it to produce control voltages which would make a VCO play at a pitch that corresponded to the note pressed. Moog's first synthesizers offered an adapted version of this as its primary control mechanism, thus fixing in the mind of the music community (and the public) of the synthesizer as a keyboard instrument.

The advent of the synthesizer keyboard greatly expanded the body of musicians to whom the device was accessible, since the piano was the primary pedagogical instrument of the time and most musicians had learned to play at least basic scales and chords on one.

Types of synthesizers Edit