ADEPT - Analogue/Digital Easier Play Theremin

A few days ago, Richard Helyer, who demonstrated his high-end optical theremins at Hands Off 2007, visited me with a first prototype of ADEPT.

Very interesting. This is, as the name suggests, a hybrid device, with regular antennas, not optical (on the next iteration - on this iteration the volume is optical) that quantises notes and feeds them to an onboard DSP based synth. (Forgive any inaccuracies - we covered quite a lot of ground over a few hours and I wasn't taking notes.)

The design is in response to a perceived demand for, essentially, a low cost synth with the keyboard removed and replaced with pitch and volume antennas. One of the aims of the prototyping process is to find the best way to determine note events, and this was the focus of much of our discussion.

But first the synth. (I'm not going to dwell on the antennas - they are currently the least developed part of the instrument and the known deficiencies with them have straight-forward solutions. Likewise the noisy power supply. The antennas are self-calibrating. Which is good.) Two oscillators, switchable between sine, square, sawtooth and variable width pulse, one of which can be detuned. (I would prefer both to be detunable. I recall reading that we perceive the average of two very close frequencies to be the note.) A ring mod with a sine oscillator. A phase sweep (not currently implemented), ADSR envelope shaping (Attack triggered my note-on event, Release by note-off) and a choice of quantisations - currently: chromatic, C Major, C Minor and atonal (i.e. Off.) but to include the other major and minor keys too. Also a simple delay (er, I think - hopefully Richard will be along soon to set me right.)

Note events are currently triggered by moving from one quantisation to the next, giving a device with the same functionality as running the back of your hand up and down a piano keyboard. Vibrato is not possible, but it does a wicked semitone trill, a fixed tremolo can be achieved with the ring-mod (digital, so clean) and a variable speed celeste can be achieved by detuning. The volume antenna also creates note events by transitions to and from silence and determines the maximum volume of a note.

A lot of this may sound familiar - eh, Fred? - and is an instance of the difference between what the customer [i]thinks[/i] he wants and what he actually needs. You may think you want your synth to be more like a theremin, but actually you need your theremin to be more like a synth. :-)

So, the next prototype will incorporate ideas from a device he designed previously - a voice to MIDI converter (sorry, can't find a link) which seems a good starting point - the theremin is very voice-like. I demonstrated how a rapid jump from one pitch to another without muting constitutes a note event, and how the volume loop can be used for envelope shaping. I also mentioned the general dislike amongst players of a fixed vibrato.

Had I thought of it at the time I would have explained that the choice of rate and extent of vibrato is an expressive device for the thereminist, dependant on the mood of music currently being played, so really can't be automated. It should be possible - subject to available processing power - to separate the small movements of a vibrato from the note being played and use them to modulate the pitch so that the top of the vibrato is in tune (I recently learned that we perceive the highest part of the vibrato at as the note being played, not the average pitch as above) whilst still recognising larger movements as note changes - and maybe even glissing nicely towards the new note during the current note's release. And - I just thought - you're going to want a pitch preview with a short releases to be sure of arriving at the right note at the right time.

The other idea I had was that it could play atonally and without the envelope shaping, but when you settle on a note (with or without vibrato) it gently nu

Gordon,
Wow!
And, the price point would be...?
Is there a web-site?
http://www.flickr.com/photos/wobblymusic/956295159/in/set-72157601111617639/ Oh, there are some pics.

Good Luck!

teslatheremin

Hi. Er, low cost. This was mentioned briefly and the target figure didn't stick in my head. Less than an etherwave.

No website.

Those in the picture are the optical theremins he showed at Hands Off. The ADEPT will be housed in a material which is largely recycled stuff, laminated. You don't get glass and marquetry on a budget.

Hi there teslatheremin - this is just to add a bit to what Gordon said. I expect the maximum price of ADEPT to be under $300 - quite probably nearer $250. This is about £125-£150 in UK money.

The prototype has lots of pretty LEDs on it which I shall probably not have on the final gadget, since although it looks more fancy, it doesn't do anything for the performance.

Gordon's idea for the atonal nudging does actually occur on the instrument - it's done by setting to chromatic operation and then adjusting the glide feature so that it is fairly slow. As the frequency shift under glide is a reciprocal curve, the approximate note can be acquired fairly rapidly, but then the final nudging can be elegantly slow.

I'm making a version of this at the moment which is in two boxes, not one. This will enable the player to set the ideal playing positions without being restricted to the box size. I imagine it will also lead to some wacky playing where users may employ their feet or whatever to operate one or both of the controls.

The reason I don't have a website is that I wish to limit production. When I was younger, I had a stationery business which really took off very well because I was promoting it successfully - but in the end it became a slave driver because people wanted so much what I was making and selling, and I did not have enough hours in the day. It made me ill at one point. As I don't want that to happen again, I shall probably continue to sell items at a finite production rate using a vehicle such as eBay, where my other stuff has been very well received (go to "community" on eBay and then put in my ID "123helyer" and look at the seller's feedback).

Also, if I use eBay, they allow me to put a link to a video in the sales text, so I can plonk something onto YouTube for example which will really show the gadget doing its stuff, and people can either bid for the item or use the "Buy it now" feature of eBay.

Bob Moog was about 12 years older than me. I recall in the 1960s, he also had to restrict sales (of his synthesizers), so that orders did not run away with him. I am not, for one moment, comparing myself to Bob, despite what one eBayer was kind enough to put on September 7th last year in my feedback - it is merely that he had a practical idea for ensuring he was not overwhelmed, and I am imitating that.

Best,

Richard Helyer

Gordon and RichardH, thanks for the reply.
I will check Ebay.

Good Luck!

teslatheremin

"A lot of this may sound familiar - eh, Fred? - and is an instance of the difference between what the customer thinks he wants and what he actually needs. You may think you want your synth to be more like a theremin, but actually you need your theremin to be more like a synth. :-)"

This is extremely interesting.. If the price and spec are close to what is being suggested, then my TherAsynth could not compete, and my congratulations go to the designer/s -

The whole issue of where the emphasis is focussed is tricky - I started out focussing on the synth, and fitting a Theremin interface.. Then did a U turn, and focussed on developing a good Theremin, with a synth interface.. I am now fixed on a modular stratergy.. Starting with the Theremin units (seperate pitch-only unit and seperate volume-filter-pan unit) which together produce a high-end Theremin.. Primary objective being playability.. This 'basic' system will also have outputs to enable control of other modules (MIDI and CV).. BUT.. The price for the basic system will be higher than ADEPT, and probably quite a bit higher! Cost comes down if quantity increases, but I would need to make >1000 units per run to approach the ADEPT price.

I am starting to think that Theremin design / manufacture is getting close to 'critical mass' - How many Theremins are sold per year? What is the global market worth? And how many of us entering this market will even get to recover our development costs, let alone make a living from them?

In the past few months I have seen many Theremins appear from nowhere - including ones using Digital + PSoC technology.. How long before we see high quality Chinese Theremins in Asda at extremely low prices? I was looking at a big Chinese keyboard selling for <£60 .. A few months ago the nearest equivalent would have been about £200.

FredM,
Not one soul, but you, has heard or played your Theremin in a critical way... yet. And, all the playability and musical perception that a Theremin may possess, is in the hands and mind of the player.

Good Luck!

teslatheremin

Fred, I don't think you and Richard are competing. You have said you are designing a high-end machine, whereas Richard's target market is not the concert thereminist.

Anyway, if the big boys were to take an interest then I guess that Sony could undercut everyone.

Hello Gordon, teslatheremin and Fred - and anyone else...

Gordon is quite right that I am not trying to compete. The way that ADEPT came about was from an awareness that people who bought my relatively cheapo gadget for making their synthesiser belonged to a different group from what I described in conversation with Gordon as the intellectual faction of theremin players. This intellectual faction, largely representative of those who attended the Symposium last July, would probably be right to consider that a significant variation from Lev Termen's theory of design would be both a detraction and a distraction. However, there is a small army of fun-seekers out there who would never be likely to have the application and musical skill to learn how to play a conventional theremin properly - we all know how difficult it is - and so I am really addressing that market. From my tiddly gadget sold via eBay, I get a lot of queries suggesting the desire to find something easier to play - and, indeed, in July last year someone put on my feedback: "I now know (cheaply) I will never be a theremin player." This honest, and probably fairly universal, comment underpins the small but definite market I will be aiming ADEPT towards.

Gordon is also right to point out that someone like Sony or Yamaha could easily make ADEPT for twopence halfpenny and sell in bulk it for - I don't know, say £69.99. In case they do, I am getting on with the final version in some haste.

All of this does not suggest necessarily that the intellectual faction will dislike or resist using ADEPT. It is merely different. Obviously it has a few advantages, since the effects, amplifier and speaker are included, and also that the heterodyne is done in software so there is no setup tuning. However, it may be that it will be less appealing to the intellectuals merely because its operation is simplified for the everyday user market. A parallel example of this occurred some years ago when I offered for free some circuitry and designs to local dioceses so that when their church organs had failed and there was no money to fix them, they could keep their old organ hardware, but secretly generate the organ sounds from concealed electronics stashed somewhere among the pipes. Their reaction was frigid enough, but when I suggested the idea to the Royal College of Organists you would think that I had offered to eat babies for breakfast, such was their level of horror at such a modern invasion of traditional technology.

Of course, I'm not suggesting that the intellectual faction would be as extreme as the RCO, but I can recognise that they may not all be welcoming of a different new kid on the block.


RichardH

Hi all,
Organists can be stogie old sticks in the mud when it comes to embracing electronic facsimiles of their big-box of a constantly pitch changing instrument. But, I say that organists are nothing in comparision to the staid bullwork of the harpsichordist's mind-set. Harpsichordists prefer nearly untunable, unplayable, pitch unstable acoustic versions to anything electronic. Luddites!
A fantastic electronic digital harpsichord has been created by R*land, that faithfully reproduces sounds of all the major schools of harpsichord tone and character. Complete with instantly attainable discarded temperaments of yore, and the crappy keyboard touch and response that is inherent in the beast. This is an electronic version that costs less than almost any low end two manual acoustic harpsichord made today. (As one may surmise, I think acoustic harpsichords should be moved closer to the dust-bin of the ancients.)
All that being said, I guess I think that most people feel safer with what they know. But, some people might like to see if the Theremin is the instrument that will finally allow them their muse. An easy to play theremin that could be purchased by someone to play, and define their own personal aptitude, or personal fortitude, to persevere to a higher Theremin experience is highly warranted. Perhaps even commercially so, on a limited basis.

Good Luck!

teslatheremin