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Company Report - Sequential

Article from One Two Testing, November 1985

We begin our story with a soldering iron. It is in the San Franciscan fist of Mr Dave Smith, a graduate of U. C. Berkeley, with a BS in Electronic Engineering and Computer Science, and one member of a progressive rock trio... this is 1972, after all.

For the creator of probably the world's most famous polyphonic synth, the Prophet-5, had a hobby. Working as an engineer in various Silicon Valley firms by day, Smith dabbled in synths by night, buying his first Mini-Moog in '72. By '74, trading on the microprocessor experience gained in his day job, he'd started building his own accessories, including an analogue sequencer. Very good, he thought, perhaps someone else might like one.

So the "Sequential Circuits" company were registered in '74 (recently shortened to Sequential) as a way of selling Dave Smith's accessories to other musicians. First products to count were the Model 800 Digital Sequencer (a slow grower in '74 and '75, but worth $20,000 worth of sales in '76) and the Model 700 Synthesiser Programmer. The latter offered a glimpse of worlds to come as it allowed owners of some ARP, Moog and modular synths to memorise control settings and recall them at one touch — early memory.

By '77 Dave Smith was ready to quit his full time job and concentrate on Sequential. As is the way with those inventions which change history and universal consciousness from time to time, Dave Smith's time, imagination and plans happened to coincide with the last part of the production jigsaw dropping into place. In the early Summer of '77, a company called SSM (Solid State Music) produced a set of 'synth' IC chips each containing a VCO, a dual VCA, a VCF and an ADSR... complete synthesiser voice, more or less.

Dave Smith watched in surprise as none of the major keyboard companies grasped the possibilities, so he took the plunge aiming to have a programmable, polyphonic synth ready for the 1978 NAMM show. Early versions — the Model 1000 and the Prophet 10 — suffered from instability. The 10, in particular, was withdrawn though some rare examples still exist, with substantial modification to fiveness.

But a little while after the NAMM show had officially opened on that first day, Dave Smith rushed onto the stand with the prototype five which was to produce such a demand. The now fully operational Sequential were to stay in a 'back-logged order situation' for the next three years.

Prophet-5s swept through the musical fraternity. They were the keyboard to have, Sequential ascribing their success to three elements — ease of use, sound quality, and the fact that they were designed by musicians, not lab techs. The earliest models laboured under supply and instability problems, partly down to the SSM chips. They were later swapped to sturdier Curtis chips in one of several revisions (Revs) the Prophet-5 was to go through in its lifetime.

There were two basic sections to the Prophet, the microprocessor, housekeeping side which would check all its inputs once every seven milliseconds, and then output the right control signals, and the analogue sound circuitry side.

In November of 1979, Sequential Circuits Inc moved into a brand new, leased 22,000 square ft factory facility, upped production, and began work on their next product — the twin manual Prophet 10 with extra keyboard modes and an onboard sequencer and cassette unit for memory expansion.

It was consolidation and magnification of the principles behind the Prophet-5, so left the world unprepared for the next Sequential product in 1981. The Pro-One monophonic synth couldn't have been further from the complexities of the 10, but despite being Sequential's first low price, high volume product, it still benefited from the wealth of knowledge in the Sequential workshop, and the rich, powerful Prophet sound. It was a remarkable success at a time when the synthesiser industry was groaning under the weight of countless sound-alike mono keyboards. By the end of 1981 Sequential Circuits had become America's largest synthesiser manufacturer.

The following year the still growing company made some dramatic moves. At the start of the year it was location. They established a European headquarters in Mijdrecht, Holland, (which ironically, but luckily for us is run almost entirely by British chaps).

Breaking from the synthesiser mainstream, but making the best of their memory technology, they created the Pro-FX series of programmable effects. While at the top of the range, their desire to stay close to musicians' needs encouraged them to spend a year developing the next step in Prophets, the touch sensitive, weighted keyboard, eight note polyphonic, Prophet t-8.

In the same space of time, Sequential had been instrumental in pooling the thoughts and resources of the world's major synthesiser manufacturers — not people best known for sharing secrets — and had got them to discuss a universal keyboard communication system to replace the unstandardised CV and gate outputs. MIDI.

The first instrument on the market to incorporate the new musical instrument digital interface was the Prophet 600, a long awaited (by the penny watching public) budget approach to Sequential polyphonics.

At which point, (since yours truly knows what's in store), how do Sequential come to design a new product. The creative process runs two ways — innovation and improvement. The t-8 and 600 were improvements on existing models, or on the principles of other synths. The next keyboard to come, the Six-Trak, was an innovation, beginning with an idea that musicians, especially home-recordists, were ready for a keyboard that could produce more than one sound at a time. The Six-Trak was a multi-timbral synth producing six notes of one voice patch, or one note of six voice patches, stacked atop each other. Like the Prophet-5 the scheme and the necessary technology arrived at the same time.

Like all Sequential projects it was given a model number during its prototype stage (the - 5's was 1000, the t-8's 1008, the 10's 1016), the concept was discussed with their test panel of musicians, the prototype built, and the result musician-ised again for further comments.

It was released in early '84, a year that saw a welter of SCI newcomers — the Drumtraks rhythm machine, Model 64 Sequencer and Max pre-set poly. In '85, further improvements and expansion followed, the Multi-trak enlarging on the multi-timbral theory and the Tom stretching the facilities of the Drumtraks.

Which brings us to the Prophet 2000 sampler which could, had the vote gone another way, have been the Shadow 2000. Sequential polled a few friends for opinions and it seemed the name Prophet still had a powerful tradition behind it. It also illustrated a conscious decision in direction for Sequential — to return to the professional end of the market with keyboards designed to musicians' expectations, not budget limitations.

Date Slate


PROPHET-5... revolutionary, programmable polyphonic, originally with 40 memories, (later expanded to 120), introduced the idea of auto-tune to polyphonics. Could play five notes at once, each with two VCOs, two ADSR envelope generators, VCF (24db/octave), and LFO. Loved for its polyphonic modulation producing lush orchestral sounds and its responsive pitch bend and modulation wheels. First version had mains switch on front panel; second (Rev 2), had switch on back and added cassette dump interface; Rev 3 swapped from SSM to Curtis chips for reasons of availability and reliability; Rev 3.2 had analogue and digital jacks to connect with Poly Sequencer. Earliest advocates included Rick Wakeman, Herbie Hancock, Jo Zawinul, George Duke, Tony Banks, but would be impossible to list all the famous let alone non-famous users. An industry standard. Nice wooden ends and a five octave C to C keyboard.


PROPHET-10... dual manual version of -5, ten voice, programmable eq and onboard cassette unit with poly sequencer.


PRO-FX... programmable, rack mounted effects including 510 phase shifter, 512 distortion, 514 mixer, 516 Parametric EQ, and 518 reverb. Up to six in a rack, all with memories for particular signal processing arrangements.

PRO-ONE... a three octave, C-C monophonic synth that won a lot of converts when mono synths were starting to get dull. Two (Prophetish) oscillators, 24dB/octave filter, two ADSR sections, noise gen, mixer, on board arpeggiator and 40 note sequencer (could remember two separate sequences). A highly impressive modulation section, very versatile for monos of the day, greatly enhanced the richness and variability of the sound. Pitch and mod wheels to boot.


PROPHET t-8... rather heavy but that's because Sequential went for a proper, wooden, weighted piano action keyboard to complement the touch sensitivity. Basic features similar to five but offered split and layering facilities for the eight voices, and a full six octave keyboard. A total of 128 memories in banks of eight, a 670 note polyphonic real time sequencer incorporated, plus second touch, individually, on each key.


SIX-TRAK... six voices, one oscillator each, that could play the same sound polyphonically, or stack up to six different sound memories on one note. Incremental programming replaced the usual Prophet edit-mode knobs, offering 100 memories and an 800 note sequencer splittable into two banks. The latter could also play back six different sounds at once, assignable after the real time sequence had been written. MIDI.

DRUM-TRAK... designed to operate with the Six-Trak, showed off Sequential's innovative talent by allowing the digital drum samples to be replayed at different tunings for each pattern. A complete song arrangement could have any number of varyingly pitched drums appearing throughout, all from the same samples.

MAX... an odd, and not entirely successful scheme, the Max offered the multi-level recording of the Six-Trak but with 80 unchangeable pre-sets to keep down the price. It could be programmed via another, connected Six-Trak or MIDI-ed computer. Very thin, silver case, but no modulation or pitch wheels. Identified by Sequential as a 'MIDI voice expander computer peripheral', but with its own keyboard.


MULTI-TRACK... the thin, convenient case of the Max, plus the programmability and multi-timbrality of the Six-Trak, but with many more features allowing keyboard splits, variable levels of stacking (one note with two particular sounds, two other notes with a different pair, etc) and extra sequencer memory space (1600 notes). On board chorus. Touch sensitive keyboard.

TOM... more clever extrapolations on the tunable pitch ideas, and the introduction of stacking to the readout channels so, for example, the crash cymbal could be hit four times in fast succession without each new hit cutting off the decay of the last. Programmable for dynamics, expandable from 2,300 note to 10,000, note memory by RAM cartridge, and also had a slot for plugging in extra sampled sounds.

PROPHET 2000... the new boy. 12-bit linear sampling, 256k memory, nominal sample rate 30kHz allowing 12kHz bandwidth for 4 sec samples per half memory (max 16 seconds at 8kHz), 8 voice polyphonic, up to 16 different samples across the five octave, touch sensitive, weighted keyboard, internal wavetables for traditional synthesis, separate ADSRs for filter and amplitude, 3.5in microfloppy disc drive included not requiring pre-formatted discs, comprehensive sample edit, loop, and cross fade facilities, on board arpeggiator, MIDI (of course).


Head of Technical Services-Europe: Robin Verner, (Contact Details)

Sales and Marketing Coordinator: Phil Sutton, (Contact Details)

Roy Goudie, (Contact Details)
European HQ: Nijverheidsweg 11C, 3641 RP Midjrecht, The Netherlands

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