Help out some engineering students!

Posted: 8/13/2012 4:50:38 AM

Joined: 8/13/2012

Hi all

We're a couple of electrical engineering students with our sights set on building a digital theremin. We're currently doing some market research, trying to work out what people actually want. 

If you could complete our 2 minute survey (just 9 multiple choice questions!) that would be a big help for us. Thanks for your time!

The survey is here:

Posted: 8/13/2012 10:53:46 AM

From: Colmar, France

Joined: 12/31/2007

I had a look onto this survey and got the impression that the goal was not a theremin design but a gesture controlled digital device with outputs to control an external synth. Thus using the theremin name and context is most probably an abuse.

I allow to suggest everybody to have a close look onto Leon Theremin's original patent (1928) to see and to understand his idea of how to create sound, and then to check if ones design ideas match with one of principles of operation described there. Theremin's name and context should only be used if the answer was "yes".

Not every gesture controlled wooooeeeeoooo-machine is automatically a theremin!

Posted: 8/13/2012 11:06:05 AM

Joined: 8/13/2012

Hi, thanks for your reply.

Yes, we understand Leon Theremin's original patent, and perhaps this is an abuse of the term. 

However, we're at the very early stages of design and trying to see if we can incorporate as much of the original invention as possible - possibly even using the heterodyne principle to generate an analog waveform and sampling the result.

If we don't end up using this we'll have look at renaming the product to keep theremin enthusiasts such as yourself happy!


Posted: 8/13/2012 11:41:11 AM

From: Canada

Joined: 8/1/2008

I think that today what IS and IS NOT a theremin is no longer defined by similarity to Leon Theremin's original patents. 

Robert Moog's SERIES 91 instruments are not even heterodyne but they are still considered theremins. 

For many people, the word "theremin" is a reference to a particular sound and they don't care if that sound is made by a 1929 RCA or a cheap Casio toy synth they picked up at a local garage sale. If it emulates those spooky moans from the old SciFi and suspense films of the 40's & 50's, for them it's a "theremin".

Posted: 8/13/2012 5:31:30 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

IMO, your survey will provide you with absolutely no useful information to guide your development direction, or give any idea about potential market etc.

For example, question 4 - You have a range of interfaces and options, but for most thereminists I dont think any of these are greatly important - but you omit every important question - not saying that what I list below is nearly comprehensive, but I think it starts to scrape the surface - whereas your survey doesnt even touch it.

>>  How important is linearity / playability to you?

>> Do you want an istrument primarily for effects or for playing melody?

>> Do you want an in-built sound engine, or to use external sound modules, or both?

>> How important is the ability to alter the sound of the instrument, and the ability to produce classic theremin timbres?

Furthermore, the price ranges you are floating - well, they really dont go high enough to encompas an instrument suitable for serious thereminists - $200+ I would see as the starting figure for any theremin with good playability, sound and any kind of output (CV, MIDI, USB whatever) - If you could make an acceptable instrument doing the above, for $200, you are doing really well!

I am talking here as a theremin developer who started out with a digital theremin based on the Cypress PSoC, and was looking at a simple capacitive sensing scheme with the PSoC doing all the work - And yes, you can make a theremin like this - but it wont compete with even the cheapest analogue theremin for many reasons... About 6 months after I started, I had a prototype - then a "theremin" appeared on the market which used a PSoC, and was cheap, and put out MIDI.... It vanished about a year later.

And by that time I had started to learn what the theremin really is, how it is played, and how critical the design is if you want any thereminist to be interested.

And I also discovered that Leon Theremin's original concept is almost impossible to beat - both in terms of cost and quality... Digital is only now starting to approach the kind of complexity and speed to start to compete with analogue, IMO - If one wants a theremin, that is;  - if you just want to chuck out MIDI note events, then its well suited and easy - but I do not regard such an instrument as a theremin, and would not pay even $100 for such an instrument.


Posted: 8/13/2012 6:15:29 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

"possibly even using the heterodyne principle to generate an analog waveform and sampling the result" - theremins-r-us  (LOL)

Why "sample the result"? If you have an audio waveform, why bother sampling this to digitise it? Sampling technology is extremely ill-suited to theremins simply because it confines the playback to cycle-by-cycle, which is one big disadvantage of all digital theremin implementations - In a heterodyning theremin the audio waveform 'morphs' dynamically as the pitch varies, which imparts essential 'distortion' that (IMO) gives the theremin a lot of its appeal.

However, you can extract pitch data from the heterodyned signal and use this to provide the outputs (CV,MIDI,USB whatever)

All the essential waveforms can be simply created using mixed-signal "heterodyning" - and this is a lot simpler for those more into "digital" than analogue - you have none of the difficulties of needing to filter an analogue signal to get a clean input for your digital circuits - mixed-signal generates an absolutely clean logic level square wave (using a simple D latch) and the circuits below show how one can produce ramps and triangle waves as well.

If you want to generate CV, MIDI, USB or whatever, a couple of PLLs will allow one to do this without the usual latencies - and if you are using a FPGA or mixed-signal processor (like PSoC 3 or 5) all the analogue, mixed signal, and digital processing can easily be fitted into the smallest of these parts - and there are analogue blocks in these parts which allow one to process the waveforms in analogue, without the quantizing problems which occur if one uses sampling technology.


Why am I telling you about all this? - simple really - so many people put loads of effort into inventing useless theremins - I was one of them!  - If that effort was spent looking at the ideas already "out there", and picking the best of these, we would all be playing far better theremins - theremins which would be suited to all skill levels, all varying requirements from sound effects to melodic playable musical instruments, to controllers for external modules..

But, instead, we (designers) come barging in with our technical focus and try to force our (usually, from a practical musical perspective) crap ideas on the musical community - yeah, technically, our ideas and inventions may be brilliant - but if people cannot play them, dont like the sound they make, or cant afford them, then we have wasted our time!

I had completed my first prototype before I had ever seen a theremin being played live, and had watched only a few you-tube performances.

My advice - Find a venue where you can see a good thereminist perform, find a good thereminist who you can consult, ideally get a few lessons on playing the theremin - and read EVERYTHING you can about theremins, both technical and musical - these actions WILL alter your design!

Posted: 8/13/2012 8:14:36 PM

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

Hi, theremins-r-us

Are you thinking about something like these?

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