8 of the most important modular synthesizers in music history

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The modular synth has evolved from a gigantic, impractical musical instrument to something that’s regularly seen in the studio and on stage. But how does a modular synthesizer differ from a conventional instrument, and how have they evolved? Scott Wilson looks at eight of the most important modulars in music history.

Few electronic music instruments inspire as much awe as the modular synthesizer. Whether they’re gigantic, room-filling systems from the 1960s and ‘70s or the compact, flexible systems of today, modulars typically have people transfixed by their mesh of patch cables, array of knobs and unusual touch plate interfaces. To the unfamiliar, they can look like impossible devices that defy the logic of what a musical instrument should be.

Loosely speaking, a modular synthesizer is an instrument broken into different components, or modules. Each module has a different function: voltage-controlled oscillators typically generate a simple sonic waveform, a low-frequency oscillator can add motion to the sound, a sequencer can play a pattern automatically, and a host of processors and effects add modulation and other character to the output. Modularity allows the user to build an instrument to their own specification.

The first modular synth was developed by Harald Bode in the late 1950s, but it wasn’t until two men on opposing sides of the USA developed their own modular systems in parallel that the format started to seep into wider musical culture. Bob Moog and Don Buchla’s instruments offered different solutions to the need for a fully-customizable instrument: Buchla’s “West Coast” method typically involves adding harmonics to simple waveforms, while Moog’s “East Coast” method involves filtering harmonics out of waveforms to create the sound you want. These ideas continue to permeate synthesizer design today.

Today, what most people imagine when they think of a modular synth is what’s known as a Eurorack system. Eurorack is a format that’s exploded in popularity over the past few years – even Coldplay are fans – but how did we get to this point? What follows is eight of the most important modular synths of the past 60 years and the role they played in the development of popular and experimental music.

Audio System Synthesizer

When pioneering German engineer Harald Bode started building the first modular synth in 1959, there were plenty of electronic devices available for making music, such as the Theremin and the Clavivox. But these instruments were quite basic in terms of the sound they could produce and the instruments they could replicate, and Bode wanted to create something that would do all the sound design and audio processing needed for making film and TV soundtracks.

Bode’s solution was to make a modular device where the signal flow was linked by cables. It meant that each component could be connected in any order the user wanted, allowing for a greater number of sound creation possibilities. Bode’s Audio System Synthesiser was a one-off, but it made a profound impression on Theremin salesman Bob Moog, who would take Bode’s idea and develop it further after he saw it demonstrated at an electro-acoustics convention in 1960.

Moog Modular

Bob Moog started developing his first commercial modular synth in 1963, after meeting composer Herb Deutsch. Deutsch wanted a device that would be capable of creating complex, experimental sounds without using magnetic tape; inspired by Bode’s system, Moog took his experience in manufacturing Theremin kits and developed his first modular voltage-controlled subtractive synthesizer.

The Moog’s size and relative cost meant that it was only really universities that could afford to pay for and store them. And the gigantic modular system might have remained obscure, had composer Wendy Carlos not got her hands one. In 1968, Carlos recorded Switched-On Bach, an LP of a Johann Sebastian Bach instrumentals reworked for Moog’s gigantic system; it was one of the highest-selling classical music recordings released up to that point and earned Carlos three Grammy awards, catapulting the synthesizer into the wider consciousness.

By the summer of 1969, Moog synths were hot property, and MoMA in New York asked if the company would be interested in putting on a concert in its “Jazz in the Garden” series. Bob Moog had no instruments that could be easily played as an ensemble due to the difficulty of patching the cables in a live context, so he created four preset boxes to facilitate easier live performance. The concert attracted 4,000 people – a huge number for something that, at the time, was a niche area of music.

After the concert, the modulars created just for the night were sold off. Emerson, Lake and Palmer keyboardist Keith Emerson ended up purchasing one of them (pictured at the top), and it ended up as a regular sight on stage at ELP gigs until his death in 2008. As he once said of the iconic synth: “When you crank it up in a stadium, it can hurt.”

Buchla 100 Series

While Bob Moog was busy working on the Moog Modular, over 2,400 miles away on the West Coast, Don Buchla was developing his own modular system. A student of physics, physiology and music at UC Berkley who was versed in musique concrète tape splicing techniques, Buchla was given a $500 grant by San Francisco Tape Center founders Morton Subotnick and Ramon Sender to devise an instrument that would eliminate the need to cut and splice tape loops to create electronic music.

Buchla’s device came to be known as the Buchla 100 Series Modular Electronic Music System. While the Buchla 100 looked like Moog’s modular, the two differed in radical ways. Moog’s method of synthesis, which became known as East Coast synthesis, uses a straightforward keyboard-oscillator-filter-amplifier signal path. Buchla’s method, which became known as West Coast synthesis, is less conventional, using dual interlinked oscillators to create complicated waveforms processed by low-pass gates rather than filters, controlled by complex or random function generators.

Buchla’s wanted to create something that didn’t fit established convention. One of the most obvious ways he achieved this was his use of a 16-stage sequencer and touch plate interface instead of a traditional keyboard. The new opportunities these interfaces offered attracted experimental musicians to the format, and Subotnick was its most vocal advocate; he used a Buchla to compose 1967’s Silver Apples of the Moon, the first piece of electronic music commissioned by a classical record company.

Buchla’s instruments have never had the widespread appeal of Moog’s, but the all-in-one Buchla Music Easel, which evolved from the 100 Series, is loved by contemporary artists such as Surgeon, Kaitlyn Aurelia Smith and Alessandro Cortini. Speaking to FACT last year, Cortini said it was the “uncertainty” in using a Buchla device that gives them their unique appeal. “They’re capable of giving things that you can’t get from anything else or anybody else,” he believes. “You develop a relationship with the instrument that is almost a human relationship.”

ARP 2500

In 1969, a third figure entered the US synthesizer market: Alan Robert Pearlman, an engineer who first saw the potential of electronic instruments as far back as 1948 as a student. Alongside fellow engineer David Friend, he co-founded ARP Instruments and set to work on solving what Pearlman saw as one of the primary issues with rival modular systems from Moog and Buchla: unstable tuning from voltage-controlled oscillators, something usually exacerbated by heat and power supply issues.

Their first commercial synth was the ARP 2500, which was known for having much more reliable oscillators than Moog’s modular. However, it differed in another significant way from both Moog and Buchla’s systems: a complete lack of patch cables. Instead, the ARP 2500 used matrix switches that lined up with arrows along the top and bottom edges of the modules, which would correspond to knobs and switches. Matrix switches have been noted for signal cross-talk, but they eliminated the mess of cables present on Moog and Buchla’s systems.

Only 100 ARP 2500 systems are said to have been manufactured, but like the early Moog and Buchla systems, they found their way into the hands of some influential musicians. The Who’s Pete Townshend was was one of its earliest adopters, using it on Quadrophenia, and French composer Éliane Radigue is considered one of the masters of the synth, using it almost exclusively until 2001. Aphex Twin even lists the instrument in the gear list for 2014’s Syro.

However, it was its appearance in Steven Spielberg’s 1977 movie Close Encounters of the Third Kind that secured the synth’s place in popular culture; the ARP 2500 was the synth used to communicate with the alien ship and Phil Dodds, ARP VP of Engineering, was its on-screen operator.

Serge Modular

Modular synths were nearly 10 years old in 1972, but they still weren’t affordable enough for the average musician. Serge Tcherepnin (a French-born composer with Russian-Chinese parentage who became a US citizen in 1960), set about devising a less expensive and more compact modular system that would be just as good as the Buchla systems installed at CalArts, where he taught. Tcherepnin started building modules in his kitchen, then offered students the chance to build their own system by paying for parts and working on a makeshift assembly line at the university.

By 1975, Tcherepnin had left CalArts to sell his modular systems commercially, offering complete synths built to specification or in kit form. They were more inspired by Buchla systems than Moog, offering functions like touch-sensitive panels instead of traditional keyboards, sequencers and random voltage generators. They used a 4U rack unit size, which was much easier for people to mount at home than the giant ARP and Moog systems, and used banana clips instead of traditional patch cables, which allowed people to stack connections.

While the manufacture of Serge modules slowed down in the ‘80s, they’ve been consistently available ever since; Random Source is one of the most recent companies to manufacture them with Tcherepnin’s blessing. Serge systems have never been as recognizable as those from Moog, Buchla and ARP, but their relative affordability made them far more common.

Richie Hawtin, Radiohead’s Jonny Greenwood and ambient legend Jon Hassell are just a few of the musicians to have used Serge modulars in their music. In 2016, Serge obsessive Jim O”Rourke told Bandcamp that he usually records five to six hours or material a day on the synth.

Roland System-100m

Over in Japan, companies like Korg, Yamaha and Roland were challenging US companies with their own synthesizers. While Moog and ARP started out building hulking modulars and gradually moved over to making smaller, all-in-one instruments, the Japanese companies skipped modulars entirely, focusing on general consumers first with devices like the Minikorg 700, Yamaha SY-1 and Roland SH-1000.

In 1975 though, Roland decided to start experimenting with modular systems. The first was the System-100, a bizarre take on the modular that offered all of the size but very little of the customizability, comprising a complete monosynth (with keyboard), expander module, sequencer, mixer and speakers. Roland’s second attempt at a modular, the System-700, was more traditional, looking more like a Moog modular than the strange musical workstation of the System-100.

However, it was 1979’s System-100m that proved to be Roland’s most popular modular system. As with Serge’s synths, affordability and size was key to the success of the System-100m. Roland’s simple wooden rack enclosure provided provide enough space for either three or five modules as well as power supply and an easy way to connect a keyboard. They were compact enough to fit in even the smallest studios and relatively practical to use on stage.

Writing in Sound on Sound in 1995, Throbbing Gristle’s Chris Carter said the System-100m was, in his opinion, “about as versatile, expandable and affordable a ‘system’ as you can get without getting your hands ‘dirty’ by going the DIY route”. Inception composer Hans Zimmer took the System-100m’s expandability to incredible lengths, building 58 VCOs, 37 VCFs, 32 ENVs, 12 VC phase shifters and nine sequencers into six flight cases, which were later enclosed in wood and built into his studio.


As the home computer market started to grow in the 1980s, so too did the number of musicians using software. At IRCAM in Paris, the institute founded by Pierre Boulez in the ‘70s as a musical research hub, Miller Puckette developed a piece of software called Max, which aimed to give composers a system for writing music with a computer. Max didn’t generate or process sound at this point, it was just a graphical environment for linking hardware synths in software, but it gave musicians the flexibility to create their own systems, much like the modular synths of the ‘60s and ‘70s.

In 1996, Puckette developed a completely new system based on his work with Max: Pure Data, an open-source environment with sound-generating and processing devices that could be linked to each other with virtual patch cords. This formed the basis of Max Signal Processing (MSP), an audio extension for Max that allowed musicians to build their own virtual synthesizers.

“I just use Max/MSP now, because in Max I can generally build the thing I need, and if I don’t know how to do that it’ll generally be worthwhile learning,” Autechre’s Sean Booth told RA in 2016. “Intellectual capital or whatever. So rather than spend me money on equipment, I spend me money—as time in learning how to build stuff.”

Today, there are countless modular synthesizer environments in software, most notably Native Instruments’ Reaktor, but Max/MSP is still widely used. It’s even inside Ableton Live as part of the popular software studio’s Max for Live expansion, allowing anyone to develop their own instruments and sequencers. Buchla and Moog’s first systems were so large they occupied a whole room; Max paved the way for a modular environment you can carry in your backpack.

Doepfer A-100

By the 1990s, modular systems had been rendered more or less obsolete by the growing market for digital and software synths, which were more affordable, more versatile and took up less space. German engineer Dieter Doepfer, who started his manufacturing career making a module for a system called FORMANT (and collaborated with Kraftwerk), believed in the format still had a place in music, specifically for creating sounds “unobtainable” by digital synthesis and sampling methods.

Doepfer wanted to create a system that sounded good, had a wide selection of modules, could integrate easily with a MIDI system and, most importantly, was affordable. The resulting Doepfer A-100 used the smallest form factor yet seen in a modular system, mounting easily into a standard 3U-sized studio rack or one of Doepfer’s ready-built cases. Doepfer’s system became so popular that other companies made their own modules for the format, which became an international modular standard for companies around the world: Eurorack.

The number of companies making Eurorack gear started as a trickle and turned into a flood. A decade ago, there were just a handful of companies in the market; today there’s over 100, most of them tiny operations with just a few employees. In 2015, even Roland and Moog began to make Eurorack modules. With no competition due to older modular formats being larger, more impractical or just obsolete, Eurorack has flourished.

“Now there are a hundred manufacturers with a thousand modules, and it’s not just me who’s lost track of it all – it’s the dealers and retailers who are groaning under this glut of modules,” Doepfer told Ableton in 2015. “Up to now, all this expansion has been good for us, mainly because the other manufacturers tended to build more exotic and unusual modules for which users still needed the standard modules that we make. We’ll just have to see how this all develops, but it does remind me of the way the stock market overheated a few years ago.”

Whether the Eurorack industry is a bubble waiting to burst is unclear, but Doepfer’s standard has changed the way people make electronic music. Eurorack modules available cover analog and digital synthesis, clones of classic drum machines, samplers and a whole range of strange and wonderful effects, a lot of which can take years to master. It’s penetrated everything from techno (Simian Mobile Disco, Surgeon & Lady Starlight, Karenn) and experimental music (James Holden, Robert Aiki Aubrey Lowe) to mainstream pop (Radiohead, Coldplay).

Speaking on synth documentary I Dream of Wires in 2011, Trent Reznor pinpointed just why Eurorack has captured the imagination of musicians around the world: “It’s brought a lot of that magic back into the synth world that got lost in the Korgs and the Yamahas and the Rolands.”

Scott Wilson is on Twitter

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