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Moog Etherwave

Theremin By Gordon Reid
Published July 2022

Moog Etherwave

Theremins have been part of Moog’s story since day one, and their latest is the culmination of all that experience.

The history of the Theremin has been widely recounted from its birth in 1919 (or perhaps 1920) to the present day. But what many of these fail to convey is just how amazing it can sound when played by a virtuoso. Perhaps the first of these was Clara Rockmore, a violin prodigy who became the foremost exponent of the Theremin, developing a method of control that allowed her to jump between notes with minimal glide and to control the pitch and vibrato with greater precision than any before her. Such was her understanding of the instrument that she even helped Leon Theremin to improve it and, by the time that World War II reached the USA, she was performing with classical orchestras and almost single‑handedly convincing a sceptical public that electronically generated music was capable of high art.

After the war, the Theremin fell into disuse as an orchestral instrument, but it found a new home in the soundtracks of sci‑fi and horror movies, providing the eerie, tremulant wail that was to become its trademark. Our story starts around this time, when a young chap named Bob Moog started building Theremins, writing articles explaining how to build them, and then selling the kits that helped to fund his education. As we all know, he was later diverted into designing and building the synthesizers that remain one of the cornerstones of the modern music industry, but Theremins always remained close to his heart and, having left Moog Music in the mid‑1970s, he founded a company called Big Briar and once more started to design and build them.

The first appears to have been a small device called the 500 Series or Model 500, which was a controller without internal sound generation. Instead, it generated two 0‑5V CVs to control the pitch and volume of external synthesizer modules. It’s not certain that any were sold, but one of the designs — based upon a brick‑shaped hardwood cabinet featuring a small control panel on the front and a screw socket underneath to allow you to mount it on a microphone stand — is clearly the ancestor of the Etherwave.

In 1991, a new instrument, the Series 91 Theremin, was released. This came in three designs called the Model 91A, 91B and 91C, and these were classic Theremins in large cabinets that recalled the large, futuristic designs of the early 20th Century. The Series 91 sold in small numbers — apparently, somewhere around 150 units — but Big Briar’s next product was the one that would reintroduce (or, perhaps, introduce for the first time) the Theremin to the world at large. Released in 1996, it was the first to bear the Etherwave name, and it was to outsell all of Bob Moog’s other Theremins combined.

I discussed the birth of the Etherwave with Steve Dunnington, who worked with Bob Moog at Big Briar in the ’90s and is now the Vice President Of Engineering at Moog Music. He told me, “The roots of the original Etherwave lie in an article that Bob wrote for the now defunct Electronic Musician magazine, which was published in February 1995 if I recall correctly. We had bought enough stock to support 500 kits’ worth of sales generated by the article, thinking that we might sell most of them. But due to Bob’s involvement it turned out to be quite a hit. Also, the timing was good because the emergence of the Internet made it easy for folks to find out about formerly obscure things. So there was a resurgence of activity around the Theremin.”

Initially released as a kit and shipped with a VHS instruction tape and a CD featuring performances by Clara Rockmore, the Etherwave’s circuit board was pre‑assembled so even those with rudimentary skills could complete the instrument successfully. By this time, I had become curious about the Theremin so I took the plunge and bought one that had been pre‑assembled by the UK importer, and I still own it to this day. A short time later, Big Briar started selling Etherwaves as finished products in a black case rather than the bare wood of the kit, and these started to creep out from the bedrooms of electronics enthusiasts and on to the stages of the world. Some significant bands and artists could be seen with them over the ensuing years and, although they were invariably used as effects generators rather than chromatic instruments, if there’s any point in its history at which the Theremin can be said to have ‘arrived’, this was almost certainly it.

Next came two more large‑scale instruments. Announced in 1997, the Ethervox boasted a MIDI output and two voice generators — the original Theremin method and a synthesised voice — that could be output simultaneously and separately if desired. Then, in 2002, Bob Moog regained the rights to his name and renamed Big Briar as Moog Music, so the next model, the Etherwave Pro (released in 2004) was the first Theremin in four decades to appear as a Moog product. This was a gorgeous design that had a unique curved and upright panel that was a million miles from the brick‑shaped Etherwave. Unfortunately, it turned out to be the last Theremin produced by Moog Music before Bob Moog’s death.

The original Etherwave had come with a document that showed how owners could customise their instruments. One of the possible modifications was the addition of CV and gate outputs, so it should come as no surprise that, in 2009, the Etherwave Plus offered these as standard. Then, in 2014, the Theremini appeared. This was a radical instrument that combined a digital sound generator based upon Moog’s Animoog software with a quantiser that made it possible to play notes accurately with far greater ease, and it made the Theremin more affordable and more playable than ever before.

Next came the Claravox Centennial which, when announced in 2020, honoured the legacy of Clara Rockmore and celebrated the centenary of the invention of the Theremin. Echoing the physical design of the Etherwave Pro, this was a much more versatile instrument with analogue and digital oscillators, pitch quantisation, an onboard delay unit, CV inputs and outputs, MIDI, USB, memories and even a software editor, thus integrating all of the technologies from traditional Theremins, the Etherwave Plus and the Theremini, and then adding more. Unfortunately, it suffered a series of production delays but, when it appeared, it was an aspirational instrument with a price to match. So, having satisfied the high end, it was again time for Moog Music to return to the more affordable end of the market. It did so by revisiting the Etherwave, which had remained largely unchanged for a quarter of a century, all of which brings us to...

The Etherwave Theremin

Although its underlying design is based upon that of the original Etherwave and the Etherwave Plus, the new model looks much nicer. There are many practical improvements too. For example, setting it up is quicker and easier because its antennae push into place rather than having to be retained using three nuts. There are also improvements to the control panel including a mute button that silences the main audio output while leaving the headphone output untouched so that you can adjust things without inflicting pain upon your audience. You’ll also find that the main audio output has moved to the rear so that the cable is out of the way. Similarly, the on/off switch has also moved to the back and, more importantly, the Etherwave now runs on 12V DC power delivered through a common barrel plug. This is a significant improvement upon the 14V AC power and DIN connector previously employed. Steve explained this to me: “For years, we made the Etherwave in a form not too different from the original design. During that time we often thought about improving it to be easier to manufacture and perhaps deal with a few peculiarities. We finally got to do this with the new Etherwave. One of those peculiarities was that the original used an AC/AC power adaptor. Those types of power supplies aren’t really made any more and shouldn’t be used, so the challenge was to convert to a DC power supply while maintaining the topologies of the original Theremin circuits. This resulted in the use of higher‑precision and lower‑noise power regulation, which contributes to the smoothness of the sound and improved stability of the revised design.” But just as important, it means that replacing the PSU — should it ever be necessary — will be easier, although it’s crucial that this is an earthed supply or, to quote Steve, “the instrument’s oscillators will be unstable and it will sound more like a vacuum cleaner through a ring modulator than a melodic instrument”.

Returning to the front panel, you’ll find four more knobs. Two of these determine the pitch and volume ranges, the first to ensure that the frequency drops to zero when you step away from the instrument, and the second to obtain the dynamic response that you want. The other two determine the timbre of the sound that it generates. With the Waveform knob turned fully anticlockwise and the Brightness turned fully clockwise, the output is a (sort‑of) rounded pulse wave with a duty cycle of a little under 30 percent. Turning the Waveform knob fully clockwise results in something that’s still pulse‑like but with a duty cycle of a little over 60 percent. Reducing the Brightness primarily affects the rise time of the waveform. You might think that this might make the shape more ramp‑like and the sound brighter than before, but the converse is true; a signal analyser shows that the number of visible harmonics and their amplitudes decrease as you reduce the value of the Brightness knob, and vice versa. But however you set it up, it produces a sound that lends itself to musical performance just as much as it does to eerie effects.

The latest version is the best yet, staying loyal to the original concept while adding functions that make it much more exciting.

In Use

To operate correctly, a Theremin needs to stand in clear space with its antennae as far away from metal objects as possible. The best ways to achieve this are to place it at the edge of a wooden surface so that its volume antenna is in free space or, better still, to mount it on a microphone stand. For the latter (which is by far the best solution), a mounting plate is supplied with the Etherwave. Having set it up, you then adjust it to obtain the playing characteristics and the tone that you want, and you’re ready to play. But, as anyone who has approached a Theremin for the first time knows, obtaining anything musical is (at first) almost impossible. Happily, the manual includes some useful exercises to get you started down the road of producing recognisable music rather than endless variations of ‘wheeee...’.

I compared the new model with my original Etherwave and, apart from small and probably negligible differences in tone, the only sonic difference was an almost imperceptible change in the response when playing low frequencies. I wasn’t certain whether this was real or I was imagining it, so I went back to Steve to ask about this. To understand his answer, you have to appreciate that the Etherwave’s initial sound is produced by the interaction of two oscillators, one with a fixed frequency and the other controlled by the distance between your hand and the pitch antenna. When the difference between their frequencies is small, they can lock together (or ‘couple’). This situation is called Zero Beat and, since the difference is now zero, silence ensues. Having explained that, I’ll hand you over to Steve. “One of the quirks of the original Etherwave is that the oscillators are mixed passively, which can lead to a bit of roughness in the tone in the bass region. In the new design, the oscillators can be mixed actively for a smoother response. But this comes at the expense of the strength of the coupling that creates the Zero Beat. So there’s a trimmer that lets you pan between active and passive mixing. If you want a more playable bass response, you can set it up for that but, if you want to set it up for strong coupling, you can emphasise that. It’s probably pretty subtle for most folks but, for very good Theremin players, we hope this will be appreciated.”

Now it was time to test the Etherwave’s CV capabilities, which are equivalent in some ways to using two long ribbon controllers, the second of which generates a gate as well as a CV. To begin, I hooked up the pitch CV and gate to a Roland SH‑101 sitting nearby. The CV tracking was correct over a wide range, but the two were out of tune with one another so I recalibrated the Etherwave’s CV range (see box). I then created a few simple sounds on the Roland, and found that almost everything I played sounded like a Theremin — not tonally of course, but in the way that the notes were articulated. The result was like having a Theremin with no control over dynamics but a much wider sonic palette.

Next, I replaced the SH‑101 with my Analogue Systems modular synth. I used the pitch CV as before and directed the volume CV to control the gain of an amplifier, and thus the loudness of the sound generated by the synth. But this seemed far too conservative, so I experimented. In one of my favourite patches, I directed the Etherwave’s audio output to one of the audio signal inputs of a mixer, its pitch CV to two mildly detuned oscillators that were also patched into the mixer, and its volume CV to three destinations: a VCA to control the loudness of the mixed audio signals, the repeat time of a delay, and the length of a reverb. The result was that, as the notes I played became quieter, the delay became slower and the reverb increased in length, which was gorgeous. Unfortunately, I am at best an incompetent Thereminist, so I would have loved to hear this patch played by an expert. But whatever your level... experiment! The results can be great.

Conclusions

While I was researching this article, Logan Kelly, the Brand Director at Moog Music, told me that more Etherwaves have been sold than all the other Moog Theremins combined and, while I doubt that they can claim singlehandedly to have kept the Theremin in the public consciousness over the past 25 years, I suspect that they have contributed more than any other, whether from Moog or elsewhere. Happily, the latest version is the best yet, staying loyal to the original concept while adding functions that make it much more exciting. But I think that I’ll finish with another quote from Steve Dunnington, who encapsulates it almost perfectly. He said: “It was an honour to keep Bob’s design alive. It’s so cool and simple, but it plays and sounds so good... if you work at it!”.

Anyone interested in the Theremin should listen to the SOS Podcast '100 Years Of The Theremin'.

www.soundonsound.com/people/100-years-theremin-podcast

Calibration

The Etherwave has access points for six trimmers, and three of these lie under the black plastic strip on its top surface. The first of these adjusts the rate at which the loudness changes with distance from the volume antenna, echoing the operation of the Volume Range knob but with a much wider range of adjustment. The other two control the frequencies of the two ultrasonic oscillators whose interaction determines the pitch of the sound that you hear, echoing the operation of the Pitch Range knob but again with far greater effect. The next is found between the Pitch Range and Waveform knobs, and this adjusts the strength of the oscillators’ coupling and, therefore, the Theremin’s ability to stay at 0Hz when something approaches the instrument without coming close enough to play it. The final two are accessed through the rear panel, and these allow you to adjust the tuning and scaling of the pitch CV output.

The Pitch CV, Volume CV & Gate

The 1V/oct pitch CV generated within the Etherwave ranges from ‑2.5V to +4.5V, with 0V being output when the note played lies an octave below middle C. This gives a range of seven octaves but may generate unexpected results if the receiving device expects only positive voltages. There’s a lag of around two cycles as this CV is calculated, which, at middle C, equates to a delay of a little under 10 milliseconds, which should be imperceptible to most players and listeners. But at the frequency of a bass guitar’s bottom E the delay is nearly 50 milliseconds, which may start to become noticeable. What’s more, if you withdraw from the Etherwave, the pitch CV may glitch. For me, this manifested as a huge upward CV sweep, so I quickly learned how to use the mute correctly. The volume CV ranges from 0V when the Theremin is silent to +10V at maximum volume, and the +10V gate is generated and held whenever the volume CV is greater than zero.

The Rear Panel

Moog Etherwave rear panel.Moog Etherwave rear panel.

The rear panel of the original Etherwave sported nothing more than a power supply input. In contrast, that of the new model looks more like the back of a conventional monosynth. It starts with a quarter‑inch unbalanced audio output. Alongside this, there’s a quarter‑inch input for a footswitch to control the mute function. You can use instantaneous or latched ‘press to open’ or ‘press to close’ switches to control the behaviour in the way that works best for you. Next come three 3.5mm outputs for the pitch CV, volume CV and gate. Having these on the rear is a huge improvement over the Etherwave Plus, which had them on the underside, making it difficult to use them when the instrument was placed on a surface. The final socket accepts the output from the supplied +12V DC power supply.

Underlying Principles

For decades, the Theremin was the only instrument that you could play without touching it. Its two antennae perform distinct functions. That on the left controls the loudness of the note, with silence ensuing when your hand is very close to the loop, and full volume being attained when you’ve moved it away. That on the right controls the frequency, with a high pitch being obtained when your hand is close to the pole, and a lower pitch (and eventually 0Hz and silence) when it’s far away. Of course, that’s a feeble attempt to describe the operation of creating music with a Theremin, no better than saying that you use your left hand to control the pitch of a violin and your right hand to control when and how loudly the note sounds. Nonetheless, it’s the underlying principle — easy to grasp, and requiring a lifetime to master.

Dorit Chrysler

Leading Theremin performer Dorit Chrysler.Leading Theremin performer Dorit Chrysler.

Dorit Chrysler is one of the leading lights in today’s Theremin community. She is the artistic director of the New York Theremin Society (www.nythereminsociety.org) and has been described as the love‑child of Nikola Tesla and Marianne Faithful, with Jane Birkin as her nanny and Björk as her Girl Scout leader. I met her at Moogfest a few years ago and attended one of her performances which was, quite frankly, remarkable. Theremin, vocals and Taurus pedals? Wow! So I thought that it would be interesting to gain some insight from a virtuoso...

“I have a strange hybrid background of having sung in the opera as a child, followed by strict classical training on vocals and piano. I then broke that up by playing in a new wave band in the ’80s followed by playing guitar in a NY noise band in the early ’90s amidst my musicology studies. But it was love at first sight when I encountered the Theremin. It seemed very interesting from a historical and musical point of view and hadn’t really been established in any genre so, with my mixed musical background, I could relate to that. I also found it interesting that a Theremin has a unique dynamic capacity that compares with acoustic rather than electronic instruments. The challenge of mastering the untouchable seemed so quixotic and hopeless that I was smitten.

“The Theremin is such an underdog in music history; it’s rarely taken seriously and is constantly underestimated. This could be for many reasons — its interface is young in comparison to the centuries‑old principles of sound production using strings, hammers and airflow, and it’s very difficult to play because the slightest body motion can change the pitch. It also presents challenges during performances because it can interact with the electrical circuits of lighting or hearing aid systems in concert halls. And, if you can’t hear it, you can’t play in tune. But it can be surprisingly varied in tone colour and applications, and it’s finally becoming known for a far wider range of sounds and repertoire. Listen to ‘Theremin100’, which was released by the New York Theremin Society. This includes more than three hours of compositions featuring 50 Thereminists from 17 countries, with tracks from genres including classical, pop, exotica and experimental music. And because the instrument is still fairly un‑established in terms of a defining sound, each player has a lot of autonomy to develop a unique sound and way of expression, perhaps even laying the groundwork for new and unexplored musical territory.

“I hope that the Theremin will become more established and better understood in days to come, and I would like to see electronic music education starting at an early age. Until very recently, teaching programs and suitable repertoire barely existed, but this is now changing. The NYTS has developed curriculums for electronic music programs starting with children as young as four and, with its ability to convert motion into sound, a Theremin can be the ideal instrument for expression and music education. I am very excited by the idea of familiarising a future generation with the vocabulary of electronic sounds and the creative freedom that a Theremin can offer, and trying to target this has been a big part of my work — developing easy, accessible and fun tutorials for players of all ages. In addition, adding CVs and gates opens up exciting new possibilities for exploring sonics controlled using a Theremin — it might even produce unique new effects that we have not heard before. I find ideas like triggering sequences using the Theremin extremely exciting, and I hope that players will experiment with these options.

“It’s true that it’s hard to master, and if you are working on playing detailed melodies it takes work and practice just like any other instrument. I also understand that many people might not choose to master something that might never be taken seriously but, with new instruments like the Claravox and Etherwave on the market, this is changing. They make a big difference to how it’s accepted, and the demand for teaching programs is growing, which makes me very happy. Hopefully they will help to produce lots of new talent across all genres.”

So how would Dorit sum up the Theremin in a single sentence? “One perfect note on the Theremin is like reaching the top of a mountain after a long climb — the view is nice!”

Pros

  • It looks and feels much more classy than the original Etherwave.
  • It’s very simple to set up.
  • The CV and gate outputs make it an unusual and exciting controller for other equipment.
  • When played well, it’s a lovely instrument.
  • It’s supplied with a proper, printed manual.

Cons

  • Like all Theremins, it’s devilishly hard to play well.
  • It’s not cheap.

Summary

The latest Etherwave is a step up from its predecessors, and the inclusion of CV and gate outputs makes it a flexible and intuitive controller for modular synths and other suitably endowed equipment. You might wonder why there’s so much fuss made about Theremins but, in the right hands, they can be fascinating and expressive musical instruments.

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