Dave Rossum
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There are names in electronic music history that became inseparable from the instruments they created. Robert Moog. Don Buchla. Dave Smith. Roger Linn.
Dave Rossum belongs in that company, although his name is less likely to appear on the front panel of the instrument. His work is more likely to be found directly beneath your fingertips.
Across more than five decades, Rossum's work has appeared inside modular synthesizers, polyphonic keyboards, analogue integrated circuits, digital samplers, drum machines, sample-based sound modules and complex digital filters. Some carried the E-mu name. Others were manufactured by companies including Oberheim and Sequential Circuits.
His career follows an extraordinary amount of electronic instrument history. It begins with a Moog modular synthesizer, then more than fifty years later, returns to modular synthesis again.
Origins
Dave Rossum did not originally intend to become a synthesizer designer. He studied molecular biology at the California Institute of Technology before beginning postgraduate study at the University of California, Santa Cruz. Around 1970, an encounter with a Moog Model 12 modular synthesizer changed direction considerably.
Rossum and friends Steve Gabriel and Jim Ketcham decided to try building a synthesizer themselves. Scott Wedge, an old friend of Rossum's with a similar interest in electronics and music, subsequently joined them.
The name E-mu Systems initially existed almost as a convenience. Components had to be ordered under something, so a company name was invented before there was much of a company to attach it to.
By 1972, Rossum and Wedge had formally established E-mu Systems. Their ambitions were considerable. Rather than producing a small, inexpensive synthesizer, they began developing large modular systems aimed at professional musicians, studios and universities.
For Rossum, these early instruments provided an education that would extend far beyond modular synthesis. Building an electronic instrument meant solving not one problem but dozens: oscillators, filters, keyboards, control systems, stability, manufacturing and the sometimes awkward relationship between what engineers intended and what musicians actually needed.
That last problem would occupy him for much of his career.
Striking the Right Chord
Early analogue synthesizers had a limitation that seems almost peculiar from today's perspective. Playing a chord was difficult. The problem wasn't simply producing several oscillators. A polyphonic synthesizer needed to determine which keys were being pressed and distribute those notes reliably across multiple voices. Rossum became fascinated by the problem.
His solution was a digitally scanned polyphonic keyboard system capable of identifying multiple notes and assigning them electronically. It was the sort of engineering development that might never become famous in its own right, yet could fundamentally change the instruments built around it.
Tom Oberheim recognised its usefulness and licensed E-mu's technology for his early polyphonic systems. Sequential Circuits subsequently used E-mu keyboard technology in the Prophet-5.
It would be too much to call Rossum the father of synthesizer polyphony. The idea had many parents. But he became one of the engineers who helped make modern polyphony practical. Characteristically, much of his contribution would remain invisible to the musicians using it.
Rossum's engineering was beginning to travel without him. Musicians could play an Oberheim or Prophet without knowing that part of the instrument's behaviour had originated inside a small California company called E-mu. That pattern would repeat throughout his career.
Rewriting the Synth's DNA
Rossum's attention also moved beneath the control panel. Working with engineer Ron Dow, he helped develop the Solid State Music, or SSM, family of integrated circuits for analogue synthesizers.
The challenge was practical. Synthesizers contained large numbers of individual electronic components, making them expensive to manufacture and difficult to keep consistent. Dedicated integrated circuits could condense functions such as oscillators, filters and amplifiers into components manufacturers could incorporate more easily.
For Rossum, this was another way of thinking about instrument design. He didn't necessarily have to build the entire synthesizer. He could solve a difficult part of the problem and allow someone else to build around it.
SSM chips subsequently appeared in instruments from Sequential Circuits, Korg, PPG and others. Once again, Rossum's contribution often sat invisibly inside machines carrying somebody else's name. It also provided E-mu with valuable licensing income. For a while.
When the Money Stopped
By the end of the 1970s, Rossum and Wedge were working on their most ambitious analogue instrument yet. The Audity was intended to be a large, computer-controlled polyphonic synthesizer, bringing together much of what Rossum had learnt about analogue sound generation and digital control during the previous decade. It was also going to be extraordinarily expensive. Then the economics beneath E-mu changed.
Sequential Circuits redesigned the Prophet-5, moving later revisions away from technologies on which E-mu had been receiving royalties. For Rossum and Wedge, the loss was significant. The income helping support their small company was disappearing just as the Audity demanded considerable investment.
Rossum now faced a problem quite different from designing a filter or keyboard scanner. What should E-mu build next? The answer began to emerge from instruments being developed elsewhere.
Rossum encountered the Fairlight CMI and saw digital sampling operating on a scale that had previously been difficult to imagine. Roger Linn's LM-1 provided another clue, demonstrating the musical potential of storing recordings of real drums inside an electronic instrument.
For an engineer who had spent a decade designing increasingly sophisticated ways of generating sound electronically, this represented a profound change of direction. Perhaps the next synthesizer didn't need to generate the sound at all. Perhaps it could record it.
Learning to Capture Sound
The first Emulator appeared in 1981. For Rossum, moving from analogue synthesis to digital sampling required a completely different relationship with sound. Previously he had designed circuits that produced or transformed electrical waveforms. Sampling meant converting an existing sound into digital information, storing it, retrieving it and turning it back into audio quickly enough to become musical.
The engineering problems had changed. Rossum hadn't. He remained interested in making complicated technology usable by musicians. Rather than attempting to reproduce the Fairlight's computer music environment, Rossum and the E-mu team concentrated on something more direct: a sampling instrument built around the familiar language of a keyboard.
The Emulator II followed in 1984 and established the approach far more successfully. Its significance wasn't simply that Rossum and E-mu had built a better sampler. It demonstrated how dramatically his world had changed in little more than a decade. He had begun by constructing enormous modular systems in which musicians generated sounds from oscillators.
Now he was designing instruments capable of capturing the sound of almost anything. Strings. Choirs. Drums. Voices. The outside world itself had become part of the instrument.
What Musicians Did With the Limitations
Rossum's relationship with musicians becomes particularly interesting with the SP-12 and SP-1200. From an engineering perspective, digital sampling in the mid-1980s involved constant compromise. Memory was expensive. Sampling time was limited. Increasing fidelity demanded resources that small, affordable machines simply didn't possess. Rossum and his colleagues therefore designed within those boundaries and musicians responded by finding ways around them.
SP-1200 users sampled records at higher speeds so they could squeeze more material into the available memory, then pitched those recordings down inside the machine. Limited resolution and conversion introduced a character that became increasingly desirable in its own right.
Rossum had designed around technological limitations. Musicians turned those limitations into technique. Again and again across his career, the final significance of an instrument was determined not simply by what its engineers intended but by what musicians discovered once it left their hands.
For someone who had begun by investigating the possibilities he heard in a Moog modular, there was something appropriately circular about watching another generation do essentially the same thing to his machines.
An Engineer With a Library
By the end of the 1980s, Rossum had another resource at his disposal that hadn't existed when he began building modular synthesizers. Recordings.
Years spent developing the Emulator family had left E-mu with an extensive collection of professionally sampled instruments and sounds.Rossum began thinking about what else could be done with them.
The Proteus, released in 1989, removed sampling from the instrument entirely. Instead, sounds derived from E-mu's library were stored permanently in ROM. For Rossum, it represented another reversal. He had spent the beginning of his career giving musicians increasingly sophisticated ways to construct sounds. Then he gave them instruments capable of recording sounds. Now he was giving them the sounds themselves.
The modular synthesizer asked musicians to construct a sound. The Emulator allowed them to record one. Proteus allowed them to choose one. Behind each shift was the same engineer asking a slightly different version of the same question: What does the musician actually need from the machine?
Returning to Synthesis
Rossum never stopped being interested in what happened after a sound entered an instrument. Sampling provided source material, but source material could still be transformed.
During the 1990s, his work increasingly explored sophisticated digital filtering and signal processing. Among the most distinctive results was E-mu's Z-plane filter technology, associated particularly with instruments such as the Morpheus.
The idea allowed complex filter responses to morph between different characteristics rather than simply opening and closing like a conventional low-pass filter. For Rossum, sampling and synthesis were no longer opposing technologies. One could feed the other.
A recording could become the starting point for transformations every bit as synthetic as the analogue oscillators with which he had begun. After two decades of digital sampling, Rossum had found his way back towards synthesis without needing to abandon recorded sound.
Back to the Beginning
E-mu Systems eventually became part of Creative Technology, and the company Rossum had co-founded gradually disappeared as an independent instrument manufacturer.
Rossum continued working in digital audio and semiconductor technology, but his relationship with musical instruments was not finished. In 2015, Rossum Electro-Music was established. Its chosen format was Eurorack.
After decades spent helping electronic instruments move from enormous modular systems towards microprocessors, sampling, digital storage and sophisticated DSP, Dave Rossum returned to patch cables and individual modules.
Yet this wasn't a return to 1972. The engineer coming back to modular synthesis carried everything that had happened in between. Analogue circuit design. Digital control. Sampling. Filtering. Signal processing. And perhaps most importantly, decades spent watching musicians use technology in ways its designers had never anticipated. The format looked familiar. Rossum had changed enormously.
Legacy
It is difficult to point to a single Dave Rossum instrument and say: this is the contribution. Perhaps that is precisely the point. His career isn't defined by one famous machine, but by repeatedly encountering a technological boundary and finding a way through it.
How do we make a synthesizer polyphonic? How do we make its electronics easier to manufacture? How do we turn a recording into an instrument? How do we work around limited digital memory? What do we do with the enormous library of sounds sampling leaves behind? How can those recordings become raw material for synthesis again?
Then, eventually:
What might modular synthesis look like after everything we've learned since the 1970s?
Few careers provide such a clear view of electronic instrument technology changing over half a century. Rossum began with a Moog modular synthesizer and the belief that he might be able to build one himself.
More than fifty years later, he is still designing electronic instruments with the same level of curiosity.
Dave Rossum's name never became as famous as many of the instruments we love and feel nostalgic for today, but look closely enough and you'll find his fingerprints all over them.
