The modern, polyphonic string synthesiser was invented in 1970 by Ken Freeman, a British keyboard player and engineer who discovered that, if you layered a note with another, detuned and slightly modulated version of itself, a pleasant ‘chorused’ sound resulted. Building prototypes with multiple oscillator banks and vibrato oscillators, Freeman refined his ideas while work flooded in, largely because nobody else could create such a warm and realistic ‘string ensemble’ sound.

In the spring of 1972, Freeman demonstrated his ‘String Synthesiser’ at the Frankfurt Musikmesse. With three oscillator banks and a sound that has become part of keyboard legend, it elicited great interest, but it was not destined to become the first string synth on the market.

In Holland, the Eminent organ company had discovered that they didn’t require multiple oscillators per note to create the ensemble effect. A new class of chip - the BBD delay line - made it possible to take the output from a single oscillator and split this into multiple signal paths, modulating the pitch of each out of phase with respect to the others to create a warm and lush ensemble sound. Late in 1972, a home organ, the Eminent 310 Unique, became the first commercially available keyboard to produce this sound, and it spawned an industry that, over the next decade, was to manufacture more than one hundred ‘string synths’ and ‘multi-keyboards’.

When Freeman’s keyboard arrived in 1973, it had been renamed the Freeman String Symphonizer. Built by Lowrey in the USA, this had lost one of the prototype’s oscillator banks, so its sound was thinner and less complex than that of its forerunner. But it was much brighter than the Eminent, and provided an interesting alternative to the thicker sounds generated by BBD-based ensemble circuitry.

Recognising that the ensemble sound appealed to rock-n-roll bands, Eminent decided to separate their string synth from the rest of the organ to create a lighter, more portable instrument that players could take on the road. The result was one of the most important keyboards ever manufactured; the Solina String Ensemble. Released in 1974 under both the Eminent and ARP names, this remains one of the most desirable of all electronic keyboards.

The interest in these instruments was not going unnoticed elsewhere and, by the time that the Solina appeared, Italian manufacturer Crumar (run by a gentleman named Mario Crucianelli) had released the first of a range of smaller and lighter string synths. But it was Mario’s brother, Piero Crucianelli, whose instruments initially had greater impact. His company was Elka, and the affordable Elka Rhapsody 490 (1974) and Elka Rhapsody 610 (1975) became instant successes. Of these, the 490 was the smaller and less flexible, but the sounds of both - simultaneously warm and edgy - ensured that they became two of the iconic instruments of the era.

Meanwhile, just along the coast, a previously unknown Italian company released the forerunner of what is possibly the warmest, lushest, and most recognisable string synth of them all. Known as both the Logan String Melody and the Vox String Thing, this produced the most wonderful ensemble sounds. When, two years later, it metamorphosed into the Logan String Melody II, Logan had extended its palette to include the most evocative cathedral organs yet heard. The Logans are legendary, still sought-after and used to this day.

Technology was now racing forward at a previously unprecedented rate and in 1975, just three years after Freeman had demonstrated his prototype, three companies released very different keyboards that were forever

to change the way that players viewed and used their instruments. Perhaps the most influential was the Crumar Multiman. Commonly accepted to be the first of the multi-keyboards, this was capable of generating piano-like, bass, brass and strings sounds simultaneously, and offered unparalleled flexibility. It didn’t sound bad either. Across the Atlantic, ARP took the concepts embodied in the Solina and combined them with the filter and contour generator of a monosynth to create the ARP Omni, a forerunner of the truly polyphonic synthesisers, later to be dubbed a ‘paraphonic’ synthesiser. Then there was the Moog Polymoog.

Often (but inaccurately) described as the first polysynth, the Polymoog lacked an ensemble circuit, but combined some genuinely polyphonic electronics with the paraphonic architecture of the ARP to provide a wider range of imitative and synthesised patches. It was unreliable and often derided, but that didn’t stop many of the most influential players of the time from creating some excellent sounds on it.

By this time, string synths and their derivatives were mainstream instruments every bit as important as electric pianos, organs and synthesisers, so it was inevitable that Japanese manufacturers would turn their attention to them. Roland had tested the water in 1975 with the RS-101 Strings, but this was curiously unsuccessful. The same could not be said of the RS-202 Strings (1976). This introduced the company’s now-classic OFF/I/II ensemble generator, and produced a transparent sound that was to become a very desirable alternative to the thicker ensembles of the European and American keyboards.

Also in 1976, Korg introduced an ensemble that reverted to Freeman’s original scheme of layering multiple, detuned oscillators to create the chorused sound. The PE-2000 Polyphonic Ensemble was a remarkable instrument, not only producing unique strings, brass and organs, but it was also the first keyboard to generate the nasal, ‘vocal’ timbre that was to characterise much of the Japanese electronic music of the mid- to late- 1970s.

Even the industrial giant that is Yamaha decided to enter the market. Known primarily for the mighty GX-1 and its lighter and more affordable (but still back-breakingly heavy and expensive) progeny the CS-80, the company took a belt-n-braces approach to string synthesis, and became the first to combine Freeman’s multi-oscillator architecture with a BBD-based chorus unit. Announced in 1977, the resulting keyboard was the SS-30, a remarkable instrument that was equally capable of producing the edgy sounds of the Freeman; the high, aetherial tones of the Solina; and the thicker, lush sounds of a conventional ensemble.

By the end of the 1970s, the keyboard-playing world was on the brink of moving in a new direction, but there were still numerous variations of the ensemble keyboard to explore. One such was the ARP Quartet (1979); small, light, cheap, and therefore surprisingly popular. Another was the Moog Opus 3. Released in 1980, this compact multi-keyboard proved to be Moog’s only foray into ensemble synthesis, but still managed to offer a somewhat different approach and another range of sounds. Then there was Yamaha’s “SK” range, which encompassed the SK-10, SK-20, SK-30, the dual-manual SK-50 and, finally, the SK-15 Symphonic Ensemble. Released in 1981, this was a cut-down version of the SK-20; a basic, low-cost string synth that offered yet another variation on the ensemble sound.

By the time that the SK-15 appeared, the world was no longer interested in the sounds produced by basic string synthesisers, and the writing was on the wall for all ensemble keyboards. Expensive polysynths such as the Prophet 5 and Jupiter 8 were capable of producing many string-like sounds, and the first of the affordable polysynths had started to appear. In the vanguard of this revolution were the Korg Polysix and the hybrid analogue/digital Roland Juno 60, genuine synthesisers incorporating chorus/ensemble sections that made them capable of imitating many of the sounds of dedicated string machines. Nevertheless, the sounds of the best ensembles remained unique, and it was the flexibility and power of the next generation of analogue and digital synthesisers - rather than any notion that they imitated dedicated ensembles - that was finally to kill off the string synths.

Released in 1983, the year that digital synthesis conquered the world, and in which the last of the true ensembles were released, the Oberheim OB-8 was the third in a series of polysynths that included the OB-X (1979) and the OB-Xa (1981). With a wider range of modulation options than its predecessors, it was capable of producing all manner of solo- and ensemble- string sounds, even without an on-board chorus ensemble. Its successor was even better. The Oberheim Xpander, released in 1984, was in many ways the most flexible analogue polysynth yet seen, and its warm string timbres became widely used as a counterpoint to the more precise but often sterile sounds of the FM synths of the mid-80s. By 1986, the string synth was dead in Europe, Japan and the USA, but elsewhere it lived on for a while longer. Behind the Iron Curtain, technology and affluence trailed the western world, and string synths were produced late into the 1980s. One of these was the Junost-21, a combination of a basic analogue polysynth and a preset ensemble keyboard, designed to be worn like a guitar and articulated using the controllers on its stubby neck. Sounding unlike any other string synth, it is a suitably strange and unusual instrument with which to end a Brief History Of String Synthesisers.

Author: Gordon Reid