The Polymoog Synthesizer

Rick Wakeman playing the Polymoog with the band Yes in the late 1970s – a primary board for Wakeman at the time.
David A. Luce, putting the final touches on the “Apollo,” in 1973, a forerunner (testbed) for the Polymoog, utilized by Keith Emerson on ELP’s Brain Salad Surgery album and tour.
A Polymoog flyer, circa 1977.

The Polymoog is a fully polyphonic synthesizer that was developed by my father, the late Dr. David A. Luce, for Moog Music Inc. during the mid 1970s. In a nutshell, it is one of the least appreciated (today) but sonically richest and responsive polyphonic synthesizers ever created. This instrument actually has a whole slew of unique sonic features, which I describe below, that only those fanatical enough to read the patents that once protected it are generally aware of. In essence, the Polymoog is a “Musical Acoustics Laboratory” of sorts that my father imbued with his vast insight into both musical sound and the wants and needs of musicians. And it had a large impact on music making in the late 1970s and 1980s.

The Polymoog is quite misunderstood though. First of all, don’t let anyone try to tell you that it’s essentially an organ, and not a “true” synthesizer, which claim is often made on websites. It is indeed not a “scanning keyboard” type synthesizer like a Prophet 5, and so it’s not capable of certain kinds of things that the Prophet 5 is. But at the same time, its “divide down” design was specially enhanced in subtle ways – as the patents lay out – that also distinguish it sharply from an organ. This, along with a bunch of other special features, provide the instrument with an unrivaled sonic richness – listen for example to the Polymoog’s “Vox Humana” sound so central to Gary Numan’s work – and with other capabilities that the Prophet 5 and other scanning keyboard synthesizers generally lack. These features include both full polyphony and velocity sensitivity, which although often downplayed by people who like the Prophet 5 are actually a huge assets for truly polyphonic styles of playing – see the example its use by Rick Wakeman.

The Polymoog was also explicitly not designed as a lead synthesizer per se, although some artists like Gary Numan and Rick Wakeman used it as such. It was designed instead explicitly as a complement to other lead synthesizers, for example, the “Lyra Synthesizer,” an instrument designed by Robert Moog (with certain contributions from my father as well), which sadly never saw production due to cost considerations. Later on it was often pitched along with the Micromoog Synthesizer, an instrument designed by Jim Scott (also with contributions from my father and others such as Tom Rhea).

So as my father used to say, to complain that it’s not a polyphonic Minimoog was to miss the point. It did what it was supposed to do, and it arguably did it better than a polyphonic Minimoog (e.g. the “Memorymoog” that came along later) would have or did, especially where truly polyphonic styles of playing are concerned. The reader might be interested to know also that there was a legal reason why the Polymoog was not a scanning type keyboard, which had to do with the fact that my father had actually invented the scanning keyboard approach himself years earlier. But that’s a story for a book to appear later…

My basic point here is that, despite whatever bias one may approach the subject with, there is not just one type of “real synthesizer,” as some attempt to claim, just as there is not one type of brass instrument, or string instrument, or keyboard instrument. This is especially the case when it comes to synthesizers, and there are actually many types of synths, and few synthesizers can do it all, and nor should they. The richness of the music created with them reflects this breadth as much as it reflects the particular special attributes of this or that instance.

This said, some criticisms of the Polymoog are certainly valid: Developed before the advent of microprocessors like the Z80, its preset capabilities are a far cry from the digital patch memory that arrived just a few years after its release. This disadvantage alone doomed the Polymoog to a relative short window of commercial viability. That said, in my opinion many of the polyphonic synthesizers that appeared in later years, whatever their strengths, still sometimes lacked a certain sonic richness that the Polymoog possesses.

As many are also wont to point out, and that my father was always the first to acknowledge, the Polymoog suffered from some real reliability issues. The primary one, and really the only one that was not and could not be corrected easily, was the tendency of the “modulation cards,” the little circuit boards associated with each which supported the all-important Polymoog IC, to come slightly use (develop an intermittent connection). Many players learned how to deal with this pretty effectively, because the designed enabled one to quickly open up the unit and reseat the cards. It’s too bad though that the board weren’t actually soldered in. This problem, and to some extent some other early (and quickly corrected) problems probably did limit the commercial sales a bit, but I don’t think to nearly the extent that some people suggest today: Competition from other polyphonic synthesizers was definitely the primary factor.

Was the Polymoog too complicated, as Robert Moog seemed to suggest in some interviews many years later? Not at all. The Polymoog analog sound generating circuits are actually elegantly simple. It had to be given the full polyphony. Aside from the problems with the modulation cards coming loose, all of that sound circuitry, and the many nice features the instrument had, all functioned beautifully and reliably. The instrument’s tuning was also rock stable, and the sound was great. The Polymoog’s ICs and the rest of the circuitry and design have also well stood the test of time, and old units can be and often are now restored, thanks to the efforts in particular of Mr. Jareth Lackey, whose restoration videos are a must for anyone interested in the topic.

And in any case, despite its short window of commercial viability, and despite its critics today, the Polymoog had an undeniable and absolutely enormous impact on music making in the 1970s and 80s, noticeably influencing the overall sound of several genres of popular music. Moreover, its impact was actually far greater than can be easily fully assessed, because the 5000+ Polymoogs sold by Moog Music Inc. – yes, the Polymoog was a pretty success for Moog Music for some years – found their way into countless studios where it was commonly used but often not listed overtly on album covers and such. Chances are you’ve a lot more Polymoog than your aware of. In any case, here are some examples of Polymoog use, two old and one new, from YouTube:

Rick Wakeman’s solo in “Wondrous Stories”: Note the full use of polyphony here, as well as the use of the instrument as a lead instrument:

Gary Numan’s extensive use of Polymoogs (as well as Minimoog for bass) in the song “Cars,” and in general on his album “The Pleasure Principle”:

A Polymoog sonic exploration by Jasper Wijnands, a.k.a Shook, an independent producer, composer and musician based in The Netherlands who utilizes the Polymoog extensively:

A Polymoog recording by synth restorationist Jareth Lackey: This recording demonstrates something fundamental to me. To utilize the Polymoog well, or really any instrument, one needs to the know the instrument well. Jareth has exceptionally good command of the Polymoog, and the sounds he achieves here are really something, and I think this piece qualifies as a nice example of sound-inspired improvisation in any case:

Sonic Attributes

Here are some of the lesser known attributes of the Polymoog that imbrue it with sonic richness:

Independent spectral envelope, as well as loudness envelope for each note: Many are unaware of the fact that the special integrated circuit that enabled the Polymoog to exist, provides a 12 db/octave Moog ladder filter for each note, such that notes are brighter when louder, become less bright as they decay, much like real instruments such as the piano. This can be verified either by experiment or a look at the patents.

Random detunings: The two oscillators for each note are slightly randomly detuned from each other across the keyboard, which adds much richness to the sound and fundamentally distinguishes the Polymoog from other “divide-down” keyboards such as organs. This can also be verified either by experiment or a look at the patents, which actually present the exactly detuning ratios.

Here are some of the better known but equally important features:

Preset Voice Stems with Formant Filtering: The Polymoog provides a very rich set of preset “sonic stems” that both a variety of preset settings for the keyboard as whole – a number of which sound like particular types of conventional instruments – but also formant filters (shown below) for these stems. Formant filters are “fixed filters” that mimic the resonant properties of physical instruments, and provide a sonic capability that few synthesizers then or now possess. Think of the “honkiness” of a horn sound for example. David Luce was actually a pioneering researcher of instrument formants, which history led to their inclusion here:

The Polymoog preset buttons: Although these are labeled as particular instruments, and do mimic some of these instruments quite well, these are better thought of as “voice stems,” which can then be processed further with things like the Polymoog’s VCF section. Note the pitch ribbon as well, which some players used a great deal. See for example Rick Wakeman’s solo in “Don’t Kill the Whale” by the band Yes.
Polymoog formant filter (fixed filter) profiles.

Resonant Filter Bank: In addition to the formant filters, the Polymoog provides a separate resonant filter bank with which you can dial up your own fixed filters. These filters also provide “emphasis,” which sounds very nice when the filter cutoffs are swept up and down manually. This filter bank actually sounds so nice that people sometimes cut these out of old polymoogs to use independently.

The Polymoog’s Resonant Filter Bank

Multiple Modulation Capabilities: The Polymoog has both frequency and pulsewidth modulation capabilities for both oscillator banks separately that greatly enhance its sonic capabilities, and moreover can be set differently for the upper and lower halves of the keyboard:

Polymoog Modulation Controls

Full Dynamics Control: The Polymoog is not only velocity sensitive, but has a sophisticated set of VCA controls, enabling great control over the loudness envelope and the degree of velocity sensitivity:

Polymoog loudness envelope and velocity sensitivity controls.

Powerful Overall VCF: The Polymoog possesses a powerful voltage controlled filter (VCF) section. This section is sometimes criticized because there is not a separate full VCF for each note (although as noted above there is filtering for each note separately as well, in terms of brightness envelope). But it’s nice also to have an overall VCF like this through which the entire signal is routed. And as such, this section is actually responsible for many of the Polymoog’s most unique and characteristic sounds, which depends on the fact that this is an overall VCF. Again, there isn’t just one type of synthesis, or one type of synthesizer. And moreover, this section provides “sample & hold” capability, which is a very nice effect for an overall VCF like this. And this VCF possesses an envelope generator as well.

Multipath Structure for Sonic Flexibility: The Polymoog is actually more like a modular synthesizer than many are aware: It’s a multipath instrument that enables one to mix the various different signal paths together in an infinite variety of combinations. The following photo shows the mixer section, along with a few other nice features, and after that is a flowchart I create to show the multipath structure more clearly:

The Polymoog mixer section. Also note the other controls providing balance across octaves, different tuning footages for the oscillator banks, the ability to choose just one or both of the oscillator banks, and the relative (“beat”) tuning between the two banks.

Backpanel Signal Routing: The backpanel of the Polymoog also enables musicians to route signals directly into or out of various sections, further enhancing the modularity of the instrument:

Powerful Foot Pedal Control: The Polymoog has a great foot pedal control unit, which is very useful for expressive control of things like the filter cutoff and volume. The pedal was rock solid, and widely used by players. See the photo at top of Rick Wakeman playing the unit.


There is a great deal more that can be said about the history and development of the Polymoog. I plan to publish a full account in coming years. But suffice it to say that this instrument remains one of the most influential and great sounding instruments of the vintage synthesizer era, and also one of the best commercial successes of Moog Music Inc. And this was no accident, but a direct consequence of the voluminous musical acoustics research and synthesizer invention work that my father, David A. Luce, performed between 1959 and 1975, all of which is expressed in fascinating ways in the Polymoog.