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Moog Polymoog

Analogue Polysynth (Retro) By Gordon Reid
Published June 1998

The original 1975 Polymoog Keyboard.The original 1975 Polymoog Keyboard.

A synth company that produced as many classic and well‑loved instruments as did Moog Music is surely allowed the odd turkey! Gordon Reid waxes critical over one of them.

There are many ways in which we can categorise synthesizers. They can be badly designed or beautifully elegant. They can be over‑priced or offer good value for money. They can be easy to transport and use, or bulky, heavy, and difficult to set up. Once plugged in, they can be sonically limited or supremely flexible; and within those limits they can be uninspiring, or can make all manner of hair stand on end. With so many permutations, you might think it highly unlikely that you would ever stumble across an instrument with a reputation for being badly designed, over‑priced, overweight, unreliable, inflexible, and that sounds — at least on the surface — terrible. Yet there was one famous instrument that, by common consent, satisfied these criteria, and more. It is even more remarkable that this instrument hailed from the most famous synthesizer company of them all. The company was Moog Music, and the instrument was the Polymoog.

In the early 1970s, Moog had decided to develop the world's greatest synthesizer. Called the Constellation, it was to have combined at least one fully polyphonic manual, a dedicated monosynth, and a pedal‑board that was a synthesizer in its own right. Moog never completed it, although its constituent parts all appeared in one form or another. Most successfully, the pedals were redesigned to become the revered Taurus bass synthesizer, a triumph surpassed only by the Minimoog itself. The monosynth appeared only once. It was originally dubbed the Lyra, but was called the Constellation by Keith Emerson, who used it as his lead synth on the Brain Salad Surgery tour in 1974. The final element in the jigsaw was the Apollo synthesizer that was to have been the core of the instrument. Emerson also used the prototype of this, but the Apollo never made it into production. Instead, Moog's Director of Engineering, David Luce, redesigned it several times before it finally appeared as the Polymoog Keyboard.

Long before most players had heard one, the Polymoog had assumed the status of a dream machine. It was 71 notes wide (unique in 1975), fully polyphonic (unique in 1975), velocity sensitive (unique in 1975), quasi bi‑timbral (unique in 1975), and it was a Moog. In a world of Hammonds, Clavinets, Mellotrons, and monophonic synthesis, it was everybody's fantasy to own one.

But even in 1975 the Polymoog was an enigma wrapped up in a conundrum, with perplexing controls and unexpected weaknesses. To understand this, we have to take a detailed look at its architecture. So, gentlemen and ladies, hold onto your hats as we delve into the innards of what is, perhaps, the world's most despised polysynth...

The First True Polyphonic Synthesizer?

The core of the Polymoog was called the Mode Selector, and Moog described this — in grandiose fashion — as a "digital logic system". It differed slightly between versions of the instrument, but the most common set of 'Modes' — originally to have been called 'Presets' — was String, Piano, Organ, Harpsi, Funk, Clav, Vibes, and Brass. (A ninth Mode, called 'VAR', allowed you to use the Polymoog as a standard programmable synthesizer.) Many commentators have described the Modes as preset sounds, but Luce saw them more as starting points that embodied the fundamental natures of the sounds named. Thus the Piano mode, for example, was percussive, velocity‑sensitive, and sounded vaguely like a Fender Rhodes or Wurlitzer EP200, while the Brass mode had a more aggressive timbre, slower attack, and vibrato. You could use the Modes exactly as programmed, simply by raising the gain of the Mode (Preset) slider in the Master Gain Controls section, and in this way you could play the Polymoog as a very basic, velocity‑sensitive, preset synth. But what were these Modes, if they were not patches created from the front panel controls? It worked like this...

The character of each Mode was defined by dedicated chips containing 142 circuits, that Moog described as "Articulators". These were the 71 amplifiers and 71 filters that shaped the sound generated by the oscillators and thus defined the fundamental timbre of the sound. As a result, the Polymoog offered independent velocity sensitivities, amplitude articulations, and timbral responses for every key, making it genuinely polyphonic in its Preset mode. You had no control over the filter Articulators, but you could bypass them by reducing the gain of the Mode output to zero, and raising the gain of the 'Direct' output. This allowed you to discover — for example — the nature of the high‑pass filter in the Harpsichord mode, or the low‑pass filtering of the Piano mode.

The blue QWERTY‑style key pad is named the "digital logic system", and selects the Polymoog's Presets: Strings, Piano, Organ, Harpsi, Funk, Clav, Vibes and Brass.The blue QWERTY‑style key pad is named the "digital logic system", and selects the Polymoog's Presets: Strings, Piano, Organ, Harpsi, Funk, Clav, Vibes and Brass.

Fortunately, the Polymoog gave you ample controls with which to manipulate the oscillators' settings and amplitude Articulators within each Mode. Many of these controls were duplicated — one for the Upper zone (the top four octaves) and one for the Lower (the bottom two octaves). This made the Polymoog, to some extent, bi‑timbral.

The first such controls — which were arranged in several programming 'panels' — related to the dedicated pulse wave and sawtooth oscillator banks. You could combine and detune these by up to ± a sixth, and the inclusion of pulse‑width modulation on the pulse waves enriched things a little further. Unfortunately, a very limited range of footages was available — merely 4' and 8' for the sawtooth, and 8' and 16' for the pulse — and, while there was a volume control for the sawtooth, the pulse was either 'on' or 'off'. But on the plus side, there were independent frequency modulators (vibratos) for the waveforms, and a phase shifter (which doubled as a primitive oscillator 'sync') on the pulse wave.

The next panel contained the VCA envelope controls, which Moog called the Loudness Contour. This modified (or maybe overrode) the VCA Articulators. Either way, editing the Loudness Contour retained the true polyphony of the Polymoog, because each note was correctly articulated according to your new envelope settings. The controls included single sliders for the attack time and sustain levels (which affected the whole keyboard) but two Decay controls — one for the Upper zone, and one for the Lower. Furthermore, and in common with the Minimoog, Decay times also doubled as Release times if you pressed the sustain pedal, or if the unconditional release buttons were 'on'. Finally, as least as far as setting the volume response of each note went, the Loudness Contour also allowed you to determine the Polymoog's response to keyboard dynamics, and a separate Octave Balance panel allowed you to set the loudness of the sounds in three bands: the lowest two octaves, the middle two octaves, and the uppermost two octaves.

Not The First True Polyphonic Synthesizer?

But it wasn't until you selected the Res (Resonator) and VCF modes that the Polymoog finally revealed its user‑programmable filters, either of which could be assigned to the Upper and/or Lower zones. Either of which...? Well, yes. The Polymoog, despite its 71 programmable envelope generators, offered just two programmable filters: a fixed filter bank called the Resonator, and a single voltage controlled filter.

The Resonator was a 3‑band equaliser similar to Moog's stand‑alone Fixed Filter Bank. It offered low, mid and high bands, each with cut‑off frequency, emphasis (filter resonance) and gain. Three filter types were available — low‑pass, band‑pass, or high‑pass — but you could not assign these individually, so, at any given time, all three bands had to conform to the same characteristic.

The Polymoog could be equipped with this set of Polypedals.The Polymoog could be equipped with this set of Polypedals.The VCF echoed, in style if not sound, the filter on the Minimoog, and featured cutoff and emphasis controls coupled to another ADSD envelope generator. However, unlike the Minimoog, the Polymoog also offered variable keyboard tracking, a dedicated VCF‑LFO, and Sample & Hold.

But the VCF proved to be the Polymoog's Achilles heel. The instrument was fully polyphonic in its Preset and Direct modes. But if you attempted to programme your own patches, the single programmable filter meant that the synth couldn't shape the frequency characteristics of any new notes if previous notes were still depressed. As a result, the Polymoog often sounded more like enhanced string ensembles such as the Korg PE1000 and ARP Omni than like later generations of polysynths.

In Use

Nevertheless, the Polymoog was an exceptional performance synth. There were no pitch or modulation wheels, but there was a ribbon controller, and the rear panel sported no fewer than 11 control inputs and outputs. The Poly‑pedal Controller (a large and expensive pedal board that combined a swell pedal, pitch and filter control, a sustain pedal, and a pedal to toggle between single and multiple triggering of the VCF envelope) used seven of these. The Polymoog's CV and Trigger outputs controlled external monosynths such as the Micromoog and Minimoog, and there were a host of other options, including three inputs that allowed you to pass an external sound source through the Resonators and the VCF. There was even an S‑TRIG input that made it possible to trigger the Polymoog from an external synth. Furthermore, the Polymoog's six outputs allowed you to send the Mode, Direct, Res, VCF, and mixed modes to independent mixer channels, for complex, layered sounds.

But even in 1975 the Polymoog's sonic problems and quirks far outweighed its benefits. Much of the blame for its uninspiring character lay within the oscillator circuitry employed by the instrument. The Polymoog used 'divide down' technology (a form of sound generation used in cheap organs and string ensembles) to create its sounds. This meant that there were just 12 pulsewave oscillators and 12 sawtooth oscillators, and lower octaves were generated by dividing the output of each oscillator by factors of 2, 4, 8... and so on. This method proved incapable of generating the powerful timbres previously associated with Moog's name.

Moreover, the near 200% failure rate of the instrument, and the need for constant modifications and updates, must have proved very frustrating for owners and very expensive for the company. And then there was the competition...

In 1975 Yamaha released the GX1. This proved to be the polysynth that everybody had expected from Moog — a three‑manual monster with a pedal board. The GX1 generated a sonic depth that you have to hear to believe and, in 1976, it bequeathed much of this to the Yamaha CS80. Each of the CS80's 16 voices was a self‑contained monosynth with twin envelopes, twin resonant filters, velocity sensitivity, and its own response to aftertouch. This was heady stuff! Even if you ignored the velocity and poly‑pressure sensitivities, the CS80 was years ahead of its competition. It had four memories, a polyphonic ring‑modulator, chorus and vibrato, a pitch‑bend ribbon, and a superb wooden keyboard. It even proved to be relatively reliable, and it for ever changed players' expectations regarding polyphonic synths.

Then, in 1978, Sequential Circuits burst upon the scene. Its first synth, the Prophet 10, was an unmitigated disaster, but what happened when the company removed half the electronics and renamed it the Prophet 5 is now the stuff of legend. Sequential's chief designer, Dave Smith, had been aiming at producing a polyphonic Minimoog, and he hadn't missed by much. In the light of such competition, the poor old Polymoog didn't have a chance.


So what were Moog doing? Nothing much. Despite the Polymoog's problems, Luce defended his design resolutely, implying, when interviewed, that players simply didn't understand his creation. He said: "The criticisms that have emerged just don't address the basic question at all".

In 1978 Moog launched the Polymoog Keyboard, a preset‑only version of the original Polymoog Keyboard (pardon?), and renamed the original instrument the 'Polymoog Synthesizer'. The new Keyboard offered 14 presets, and you could slightly modify these from the front panel, but with nowhere near the control you had over its forerunner.

It took Moog six years to respond to the CS80 and four years to respond to the Prophet. By this time the company had ceased production of the Polymoog Synthesizer and the Polymoog Keyboard, as well as the Minimoog and the Taurus pedals. Consequently, the Memorymoog, the synth they launched as their response, looked like no other Moog synthesizer. With a return to wooden end‑cheeks, a robust chassis, and attractive panel hardware, it looked like a top‑of‑the‑range instrument and, finally, it delivered. Of course, nothing is perfect, and the Memorymoog lacked the Polymoog's velocity sensitivity, so piano‑type patches proved unsatisfactory, as did all manner of percussive and plucked sounds. But, by way of balance, its ensemble strings, brass and synth pads have rarely been surpassed.

A year later, the Memorymoog Plus superseded the original model, adding a primitive MIDI interface and a 4000‑event sequencer. Then, in the summer of 1983, Moog showed that it had one final trick up its sleeve. It demonstrated the SL8 only once, and in that brief glimpse we saw an instrument that looked very much like a Memorymoog, but with a digital oscillator, analogue VCF and VCA, plus micro‑processor generated envelopes and modulation sources. This architecture would have made the SL8 much more affordable than the Memorymoog but, unfortunately, the Yamaha DX7 had already hit the streets, and analogue synthesiswas, for a decade, on the way out. Starved of income, Moog (the company, not the man) was bankrupt, the SL8 never made it into production, and the company folded.

The Polymoog In 1998

So has the Polymoog had a rough ride? In many ways, the answer is "no". Analogue polysynths are desirable for two reasons: they are simple to use, and they sound lush. The Polymoog barely satisfies these criteria. Its controls are less than intuitive and its basic sounds are thin (although coaxing something better from one can occasionally be a rewarding experience). Of course, not all synths have to be fat, bombastic dinosaurs, and not all sounds have to dominate a mix with huge Minimoog‑esque filter sweeps. Indeed, I remember Tony Banks telling me how he replaced his RMI Electrapiano's Organ mode with the Polymoog's thin organ‑style sounds.

The 1978 Polymoog keyboard, a preset‑only version of the original instrument.The 1978 Polymoog keyboard, a preset‑only version of the original instrument.

On the other hand, most players with professional experience of the Polymoog are glad that they no longer need to put up with its limitations and breakdowns. There remain a few enthusiasts who feel that its revival — hanging onto the coat‑tails of the current fashion for all things analogue — is justified, but I'm not one of them. As a long‑time owner of a pre‑1978 Polymoog Keyboard (ie. the synthesizer version) I can confirm that it's an annoying instrument that usually fails to live up to its promise. Add to that the expenses incurred in keeping it fully functional throughout the '80s and '90s, and it becomes hard to justify its existence. Indeed, it developed a new fault even as I was preparing this retrospective. Sure, somebody reading this is going to write in to flagellate me with stories of a beloved and flawless Polymoog that has never seen the business end of a screwdriver... but would you be that lucky?

The Polymoog, as Keith Emerson says, was an important keyboard, and it deserves its place in history. But that is where it should stay.

Keith Emerson's Perspective

"The Polymoog design was partly the result of the very good relationship I had had with Bob Moog. Unfortunately, the production version came out when Bob was becoming interested in digital synthesis and was considering leaving the company. Once Bob had decided to leave Moog Music, I felt that, if I couldn't deal with him, it was hardly worth continuing with the company.

"It was around this time that I heard of the Yamaha GX1, the world's first true polyphonic synth, which, even today, is a glorious synthesizer. It was a turning point for ELP: the GX1 looked great, and I always felt a certain confidence standing behind it. In contrast, the Polymoog was unsuccessful largely because Norlin Music was interested in quick sales and didn't take the time to market it correctly. Nevertheless, it was a hugely important keyboard."

The Prices

The Polymoog appeared with a price tag that put it beyond the reach of most players. It is, therefore, surprising how stable the price remained until the instrument was deleted. If you must buy one, please don't pay more than these guidelines. Just think what else (ie. more flexible and more reliable) you could get if you paid more...






Polymoog Synthesizer*










Polymoog Legs





Polymoog Keyboard*





* These prices included legs, but not the Polypedals.

Hear It For Yourself

Despite its reputation, the Polymoog graced many — particularly 'progressive' rock — recordings in the 1970s. They may sound dated in 1998, but it's worth checking out the following, if only out of curiosity:

• Abba Arrival
• Gary Numan 'Are Friends Electric?'
• Gary Wright Dream Weaver
• Genesis Then There Were Three
• Patrick Moraz The Story of I
• Saga Saga, Images at Twilight, Silent Knight, Worlds Apart
• 10cc 10 Out Of 10
• Tomita Bermuda Triangle
• Yes Going For The One, Tormato

Define A Polyphonic Synth...

No synth should be considered polyphonic simply because it can play all its notes simultaneously. To be truly polyphonic, the instrument must shape each note individually. If you play a second (or third, or fourth...) note, each must follow its programmed tonal and dynamic development without deference to any notes that are already playing. For all but the most basic sounds, this requires at least one amplifier and one filter per note.

And Finally... Modes

The Polymoog's confusing nomenclature used the word 'mode' in two distinct ways: firstly, to describe the eight sound types selectable; and, secondly, to describe the four output modes — Mode, Direct, Res, and VCF — available. I have used 'Mode' for the former, and 'mode' for the latter.

Published June 1998