The moog modular synthesizer was never designed to leave a room. It was a set of electronic modules joined by patch cables, sold mainly to universities and record companies, and it weighed and cost what a small car did. That a handful of rock keyboard players dragged one onto a stage in front of ten thousand people is one of the odder decisions in the history of the genre, and it changed what progressive rock sounded like. Here is what the machine was and what it took to use one.

Trumansburg, 1964

Robert Moog was a doctoral student building theremins when he met the composer Herb Deutsch at a trade fair in 1963. Deutsch was making electronic music by splicing tape, which was slow and unmusical work, and the two discussed a portable electronic studio instead. Moog received a sixteen-thousand-dollar grant and began building in Trumansburg, New York. He and Deutsch demonstrated the result at the University of Toronto in 1964, and orders followed from an Audio Engineering Society convention.

The technical key was the voltage-controlled oscillator, built around silicon transistors with an exponential response, and the standard Moog chose for it: one volt per octave. Everything downstream follows from that decision, and the industry still uses it. The only part he patented was the ladder filter, granted on 28 October 1969, which is the component responsible for what people mean by the Moog sound when the filter is driven hard.

How you actually use one

A modular Moog is a collection of separate modules – oscillators, amplifiers, filters, envelope generators, noise sources, triggers, mixers – and it makes no sound at all until they are connected with patch cords. Any module can control any other. That is the source of both its range and its difficulty: there is no sound waiting to be played, only a set of parts and a wiring problem.

Moog also made a decision his competitor Don Buchla refused to make, and fitted a keyboard. Buchla thought a keyboard restricted electronic music to the tempered scale; Moog concluded that musicians wanted one, and that putting a keyboard in the photographs communicated that the machine was for making music. That single choice is why progressive rock has Moogs in it and not Buchlas.

The known weakness was tuning. Small changes in temperature make the oscillators drift, and Moog did not prioritise stability because his early customers were experimental composers not writing conventional melodies. On a hot stage, in front of an audience, that becomes somebody’s problem every night.

Price, scarcity and Switched-On Bach

At roughly ten thousand dollars the Moog was far cheaper than its institutional competitors, and unlike them it could be played in real time rather than programmed with punched cards. Even so, by 1970 only twenty-eight modular Moogs were owned by musicians; the rest belonged to universities and record companies. The record that changed the commercial picture was Wendy Carlos’s Switched-On Bach in 1968, which won three Grammy Awards and became the first classical album certified platinum, and which demonstrated that a synthesizer was not a noise machine.

A footnote that says something about how the instrument was received: the American Federation of Musicians negotiated a temporary ban on its commercial use, fearing for session players whose string and horn work it might replace. Moog thought the union had misunderstood what the machine was, imagining buttons labelled with musicians’ names rather than an instrument that had to be learned.

Onto the stage

Keith Emerson is the player who took the machine out of the studio. His touring system, assembled from a large number of modules, stood about three metres high, weighed around a quarter of a tonne and needed four people to move – equipment on the scale of a stage set rather than an instrument. He acquired his first Moog around 1970, funded by the band’s record deal, and it is behind the ELP catalogue of the early 1970s, from Tarkus (1971) to Brain Salad Surgery (1973). The full account of his rig is in Keith Emerson’s Moog.

Beyond ELP, the 1970s saw heavy use by Yes – the keyboard wall around Close to the Edge (1972), covered in Rick Wakeman’s keyboards – and by Tangerine Dream, who built an entire body of work on electronics rather than treating them as a colour.

Why the Minimoog ended it

The modular system is the reason the Minimoog exists. Finished in early 1970, it took the same components, wired them together permanently and put them in a case one person could carry, at a price a working musician could meet. A patchable system can do far more; a fixed one can be switched on and played. For everyone except the few prepared to tour with a wall of modules, that settled the argument. The story of the smaller machine is in the Minimoog in prog rock.

What the modular left behind is the vocabulary. Voltage-controlled oscillators, envelope generators, filters, noise sources and sequencers became the standard furniture of every synthesizer since, and the ladder filter is still being reimplemented in hardware, plug-ins and digital signal processors more than fifty years after its patent.

A note on attribution

Because analogue synthesizers of this period sound broadly similar, the modular Moog gets credited for a great many parts that may have come from an ARP, an EMS or the Minimoog sitting next to it. Where a player has said which machine produced a sound, this site says so; where the claim comes from a forum, it is left out. The same caution applies to the specifications of touring rigs, which changed constantly and are mostly reconstructed from photographs.

Go deeper

The related instruments are covered in the Minimoog, Keith Emerson’s Moog and the Moog Taurus pedals, with the full survey in the guide to prog rock gear. For the players, see the best prog rock keyboardists, and for the records the best Emerson, Lake & Palmer albums. The British scene this machine reshaped is the subject of Beyond the Thames, the second book in my Beyond the Sound series.

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