Sequential Circuits

Dave Smith's Prophet-5 — the first programmable polysynth

Dave Smith invented the modern synthesizer. Not once, but twice. First with the Prophet-5 — the instrument that made polyphonic synthesis programmable and practical — and then with MIDI, the universal standard that let all electronic instruments talk to each other. Sequential Circuits was a small company that changed everything, and the Prophet-5 remains the yardstick against which all analog polysynths are measured.

History

Dave Smith was a young engineer in Silicon Valley who loved music and saw the potential of microprocessors to solve the biggest problem in synthesizer design: polyphonic memory. Before the Prophet-5, polysynths like the Oberheim Four Voice and Yamaha CS-80 were either prohibitively expensive or couldn't store and recall patches. Every time you wanted to change sounds, you had to manually adjust dozens of knobs — a nightmare for live performance and a serious drag in the studio.

Smith's insight was to use a microprocessor (the Zilog Z80) to scan and store every parameter of a synthesizer patch, then recall it instantly at the press of a button. The Prophet-5, released in 1978, was the first fully programmable polyphonic synthesizer — 40 memory locations that could store and recall complete patches, five voices of two-oscillator analog synthesis, and a sound that was warm, precise, and immediately musical. It was a revolution.

The Prophet-5 was adopted by virtually every major act of the late 1970s and early 1980s. Its sound — clear, balanced, and supremely versatile — made it the default polysynth for pop, rock, new wave, and film scoring. The instrument went through three revisions: Rev 1 and 2 used SSM chips and had a rawer, more characterful sound; Rev 3 used Curtis CEM chips and was more stable and refined. Debates about which revision sounds best continue to this day among collectors and enthusiasts.

Smith's next world-changing contribution came in 1983, when he and Ikutaro Kakehashi of Roland co-developed MIDI (Musical Instrument Digital Interface). Before MIDI, electronic instruments from different manufacturers couldn't communicate with each other. MIDI created a universal language that allowed synthesizers, drum machines, sequencers, and computers to work together seamlessly. It is arguably the single most important technical standard in the history of electronic music, and Smith and Kakehashi were jointly awarded a Technical Grammy in 2013 for their work.

Sequential continued producing innovative instruments through the 1980s. The Pro-One (1981) distilled the Prophet-5's voice architecture into a monophonic synth of exceptional quality. The Prophet-600 (1982) was the first synthesizer to implement MIDI. The Prophet VS (1986) pioneered vector synthesis, using a joystick to crossfade between four different waveforms in real time — a concept that influenced the Korg Wavestation and many subsequent instruments.

Sequential Circuits went bankrupt in 1987, a victim of the fierce competition and rapid technological change that characterized the 1980s synth market. Dave Smith worked at Yamaha and other companies before founding Dave Smith Instruments in 2002 (later renamed Sequential in 2015 after reacquiring the brand name). The new Sequential has produced acclaimed instruments including the Prophet Rev2, OB-6 (a collaboration with Tom Oberheim), and the Prophet-5 Rev4 — a faithful reissue of the original. Dave Smith passed away in 2022, but his contributions to electronic music — the programmable polysynth and MIDI — are permanent gifts to every musician on Earth.

Notable Instruments

Prophet-5

The Prophet-5 is the standard. Every analog polysynth released since 1978 exists in its shadow. Its five-voice, two-oscillator architecture with a resonant lowpass filter, polymod section (allowing one oscillator and the filter envelope to modulate the other oscillator's frequency and pulse width), and 40-patch memory defined what a programmable synthesizer should be. The sound is clear, precise, and balanced — less aggressively warm than an Oberheim, less raw than an ARP, but supremely versatile and always musical.

The Prophet-5's user list is essentially a who's who of late 20th-century music. ABBA used it on The Visitors. Phil Collins played it on "In the Air Tonight." Talking Heads, New Order, Japan, Depeche Mode, The Cars, Thomas Dolby, and Peter Gabriel all relied on it. John Carpenter used it to score Escape from New York. Radiohead's Jonny Greenwood has made it central to the band's sound. The Prophet-5's influence on how synthesizers are designed, marketed, and used has been so profound that it's impossible to imagine the history of electronic music without it.

Pro-One

The Pro-One took the Prophet-5's voice architecture — two oscillators, the same filter, the same polymod section — and packaged it as a monophonic synth with a sequencer, an arpeggiator, and a price tag that was a fraction of the Prophet-5's. It was, in many ways, Sequential's answer to the Minimoog — a performance monosynth with a distinctive character. The Pro-One's sound is bright and aggressive, with a filter that self-oscillates beautifully and a polymod section that can produce everything from subtle FM textures to screaming chaos.

Vince Clarke of Depeche Mode and later Erasure and Yazoo used the Pro-One as his primary instrument. The bass line on Depeche Mode's "Just Can't Get Enough" is pure Pro-One. The instrument's aggressive character and built-in sequencer made it a favorite of early industrial musicians — Skinny Puppy, Front 242, and Nitzer Ebb all used it. Its combination of exceptional sound quality, flexible modulation, and relative affordability made it one of the best monosynths of the analog era.

Prophet VS

The Prophet VS was Sequential's most forward-thinking instrument and, tragically, its last major release before the company's bankruptcy. It pioneered vector synthesis — a technique that placed four different waveforms at the corners of a two-dimensional grid, with a joystick allowing the player to smoothly crossfade between them in real time. This created evolving, animated timbres that were unlike anything subtractive analog synthesis could produce.

The Prophet VS's digital oscillators had a bright, crystalline quality that was distinctly different from analog warmth, but the vector mixing gave those static waveforms a sense of movement and life. Brian Eno used it. Vince Clarke adopted it enthusiastically. Film composers appreciated its ability to produce slowly evolving atmospheric textures. The vector synthesis concept that Dave Smith pioneered with the VS was later adopted and expanded by Korg in the Wavestation and Yamaha in the SY22/TG33, but the Prophet VS remains the pure, original expression of the idea.

All Models in Archive (4)

Analog Synthesizers

• Pro-One - 1981-1984
• Prophet-10 - 1980-1984
• Prophet-5 - 1978-1984

Digital Synthesizers

• Prophet VS - 1986-1987