From Wikipedia, the free encyclopedia

Sequential Circuits Inc. (SCI) was a California-based synthesizer company that was founded in the early 1970s by Dave Smith and sold to Yamaha Corporation in 1987. The company, throughout its lifespan, pioneered many groundbreaking technologies and design principles that are often taken for granted in today's greatly enhanced world of music technology. Sequential Circuits was also pivotal in the planning, designing, and supporting of 1982's groundbreaking music technology, MIDI.

Sequential's first products were sequencers and programmer devices for third-party synthesizers.

The first synthesizer they came out with was the very successful Prophet-5, released in 1978. This was the first affordable, fully programmable polyphonic analog synthesizer, and became very popular in the early 1980s. In combining full microprocessor control with low-cost synthesizer module chips made by Solid State Music and later Curtis Electromusic, Sequential was able to make a relatively low-cost keyboard with five voices of polyphony. This revolutionary principle of combining five similar analog voices with easy editing and programming in one case became then the standard for a polyphonic instrument, making it possible to play real chords on a synth as e.g. on a piano. With the addition of patch storage, the synthesist was able to cycle through many different (up to one-hundred) sounds in a sitting, without having to re-calibrate the instrument for every switch. These were very unexpected developments in the synthesizer industry, especially from a previously unknown company that operated out of a California garage. Dave Smith designed, programmed, and built the Prophet in less than eight months.

They followed this successful debut up with a ten-voice version of the Prophet, Prophet-10 in 1980, coming in a massive dual-manual package with a digital sequencer and the ability to play two different timbres at once. A monophonic version called the Pro-One followed, becoming particularly successful with sales of over 10,000 units.

Sequential was also instrumental in developing MIDI, and came out with the first MIDI synthesizer in late 1982: the Prophet 600. At the 1983 NAMM convention, this instrument successfully communicated with a Roland JX-3P synthesizer in the first public demonstration of the MIDI protocol.

The Prophet-T8 (1983) featured an 76-note wooden keyboard (uneven A to C), and implemented a basic MIDI interface. It had an eight-voice structure that was similar to that of the Prophet 5. The weighted, velocity and aftertouch-sensitive keyboard mechanism was so well-liked that New England Digital adopted it for use in their Synclavier workstations. Dave Smith himself keeps and maintains a T8 unit as the main controller keyboard in his home studio.

The Six-Trak (1983) was one of the first multi-timbral synthesizers, equipped with MIDI and an on-board six-track digital sequencer. It was designed as an inexpensive and easily portable 'scratch-pad' machine for trying out arrangements. New iterations of this technology appeared in the Multitrak and MAX keyboards, which also signaled an ill-fated leap into the undeveloped realm of computer-based editing and sequencing. Sequential's relatively unsuccessful experiment in this field set the stage for further financial troubles.

They came out with two drum machines: the Drum-Traks and the Tom. In late 1985, the Prophet-2000 sampler was released.

The Prophet VS vector synthesizer, which was Sequential's only digital synthesizer, came out in early 1986. Boasting a synthesis scheme known as vector synthesis, it combined the revolutionary digital waveform generator and vector joystick to the tried and proven analog Curtis filter, and resulted in a unique instrument with a very distinct sound. It still sees heavy use today despite its reliance on rare custom components with a high failure rate.

The last musical instrument that they commercially released was the Studio 440'. This $5000 unit looked like a drum machine; and combined a sampler and a sequencer to make a music composition workstation. This preceded the release of the popular Akai MPC sequencers by several years, which were designed by Roger Linn, a good friend and frequent collaborator of Dave Smith.

They were working on the Prophet 3000 16-bit sampler in 1987 before going out of business and being bought out by Yamaha. Yamaha then sold the few completed units for a very low price. Like most of the Sequential line, this sampler contained features that were far ahead of their time, such as automatic pitch detection and keymapping, a remote control interface, and facilities for easily looping and trimming sampled sound. Many of these technologies were later included in Yamaha's A-series samplers.

Support for Sequential Circuits instruments is now provided by Wine Country, which is run by ex-sequential employee Dave Sesnak. After a short stint at Yamaha, which bore fruit in the form of the SY22 and TG33 vector synthesizers, several members of the Sequential team became part of the Korg R&D department. Dave Smith consulted with Korg at this time, and the powerful and memorable Korg Wavestation synthesizer was born. These two synthesizer designs borrowed certain elements from the Prophet VS, but broke new ground in making full use of the new digital technology that had developed in the years since.

Sequential Circuits products are popular targets for simulation or emulation in software synthesizers, with companies such as Native Instruments and Creamware offering virtual instruments inspired by the Sequential designs. Various analog modeling synthesizers also include presets to emulate Sequential's signature sounds. For example, the Clavia Nord Lead includes a preset patch bank which contains faithful recreations of the Prophet 5's factory sounds.

• Dave Smith Ego Museum
• The Birth of the Prophet VS
• The Prophet VS - Retrosound
• The Prophet 600 - Retrosound