December 2021 - Urs Gaudenz and Thierry Frenkel


In the December 2021 episode of the Theremin 30 podcast, host Rick Reid plays music from the USA, the Netherlands, and Canada. Rick's interview guests are Urs Gaudenz from Gaudi Labs and theremin luthier Thierry Frenkel, collaborators on the new Open Theremin V4. 

▶️ Listen to this episode on Spotify.


*The full-length recordings featured in this show were used with the knowledge and permission of the artists and composers. Please support the artists by visiting their websites, purchasing their recordings, and attending their performances. 







Copyright 2021 Rick Reid 



David Brower  0:04  
This is Theremin 30, thirty minutes of Theremin music news events and interviews with a new episode about every 30 days. Now here's your host from Denver, Colorado USA, Rick Reid.

Rick Reid  0:19  
Hey there, welcome to the Theremin 30 podcast for the month of December 2021. I'm sorry I didn't release an episode for November but I just got too busy with some of my other projects. So hopefully you took the opportunity to go back and listen to some of the past episodes you may have missed. I also want to mention that I had a birthday shortly after I released the October episode, several listeners and thereminists from around the world gave me a very nice surprise. Without naming anyone in particular, I want to thank everyone who made it such a fun birthday for me. I really appreciate your support and your friendship. Speaking of fun, I think I've got some really fun theremin music to share with you this month from the USA, the Netherlands, and Canada. And now visit with two special guests: Urs Gaudenz and Thierry Frenkel. We're going to talk about the new open Theremin version four. Let's get the music started now with a pair of tracks that show the wide range of possibilities the yheremin presents. In a couple of minutes we'll hear music from Thorwald Jorgensen, but first up thereminist Aileen Adler is featured in a new release by Destroyer Creator, the music project of Austin, Texas based recording artist David Coloma. It's one of the shortest and loudest songs to ever be in this podcast series. And it's appropriately titled "Theremin Metal."

Rick Reid  8:44  
We started the show with "Theremin Metal" by Destroyer Creator featuring Aileen Adler. Then we calm things way, way down with Thorwald Jorgensen and pianist Kamilla Bystrova and their arrangement of "Valse Triste" by Jeann Sebelius. You can see music videos for both of these songs on the Theremin 30 playlist on YouTube. There's a link on the Theremin 30 website. Thorwald has a couple of concerts coming up soon. I'll tell you all about them in the Theremin 30 calendar and get out your crayons for a new track by Stephen Hamm. That's after a quick break.

Rick Reid  9:28  
We take some time out of every podcast episode to look at the Theremin 30 calendar of theremin events. Carolina Eyck will be performing Kalevo Aho's "Theremin Concerto" in Krefeld, Germany, December 7 through the 10th. On December 11, Thorwald Jorgensen performs with percussionist Peter Elbertse, in Hilversum, Netherlands. On December 21, Saori Kojima will lead a couple of introductory theremin workshops in Kyoto, Japan, and Thorwald Jorgensen will take the stage again on January 2 in Hoge Zvaluwe, Netherlands. For details about these events and more, check out the interactive calendar on And if you have an event you'd like me to put on the calendar send me all the details through the website Twitter or Facebook, Vancouver BC Canada's psychedelic thereminist Stephen Hamm has a fun new tune with an even funner - is that a word? funner? I say it is - an even funner promotion. When you buy his new Theremin Man coloring book you get downloads of this single and two other tracks as a bonus. Here is Stephen hamm with "Galactic Man."

Rick Reid  14:03  
That was Stephen Hamm's new single "Galactic Man." You can get that song and two more tracks when you buy his new mini coloring book at Stephen will host a Theremin music and coloring party on December 16 at the Lido in Vancouver. There's a link to more details on the Theremin 30 calendar. I've got a holiday classic from Armen Ra later in the show. And up next, I'll visit with Urs Gaudenz and Thierry Frenkel about the new Open Theremin version four, so stay tuned.

Rick Reid  14:52  
Gaudi Labs in Switzerland recently released the Open Theremin version four, one of the most affordable and versatile theremins available on the market. I ordered one as soon as it was announced, and I've had a great time playing it. A couple of weeks ago I visited with its lead designer, Urs Gaudenz, and a key collaborator, Thierry Frenkel, from their homes in Switzerland and France. Urs and Thierry, welcome to the Theremin 30 podcast. 

Urs Gaudenz  15:18  
Hi, thanks for having us.

Thierry Frenkel  15:20  
Thanks for the invite. 

Rick Reid  15:21  
I've had Urs on the show before talking about the open Theremin v3. But now you've got v4 that just came out. What inspired the new version of your theremin?

Urs Gaudenz  15:32  
There have been versions before v3 as well. So it's kind of a project that evolves. And it also changed over time. In the beginning, it was really just an experimental circuit, then it became kind of a standalone circuit and then combined with the Arduino, and now it got independent of the Arduino. So it grew out of the Arduino board shields design and now became kind of standalone instrument.

Rick Reid  15:56  
Thierry, you've been involved with the firmware quite a bit in both v3 and the new version.

Thierry Frenkel  16:01  
I thought when I bought my first v3 that it was a beautiful design. And it worked well for engineers, but it had a lack of musicality. And so I decided to rewrite parts of the firmware to improve the firmware to make it more musical, especially on the expression on the volume side, because there the control wasn't what it could have been. Furthermore, for the v4, I added all the software which was needed to make the additional hardware, the new outputs for volume and pitch CV, working.

Rick Reid  16:40  
One thing that surprised me about the v4, because I just bought one a few weeks ago, is that I didn't have to solder any parts. I'm not very good at soldering, and the v3 required about 40 or 50 different soldering points. So I was thrilled to be able to open up the box and have a working theremin within a few minutes. 

Urs Gaudenz  16:58  
In the beginning, it was kind of a more electronic hardware project. And I thought it was interesting for people to do some soldering and to do some programming. But I noticed that more and more in going to music community where people are not so familiar with soldering and programming. And so with the integration of the Arduino, it kind of was I think, at the point to give up the hand soldering and do it all as a working instrument. For the v3 already, I saw that a lot of people prefer building nice cases, building different knobs, different designs. So this is still possible. I think there is plenty of do it yourself opportunity in the instrument without having to do the solder joints that you mentioned,

Rick Reid  17:35  
one of the ways that it can be expanded or modified involves the Eurorack synthesizer format. Can you tell me more about how that works?

Urs Gaudenz  17:43  
Usually, when I do a new version, I invite the designer and in this case for version four, it was Peter van der Beek, a Danish designer, and he didn't know much about the terramin before, I think so he was just looking around and making up his mind about the design. And then when he proposed the design of version four to me, I said that looks really much like a module for a modular synthesizer. And he didn't design it really like that. But I said like, if it really looks so close to a module for a modular synthesizer, he should have the right dimensions because otherwise people will try it and will be annoyed. So then we decided, okay, let's do it and fit it into this format. And I think it fits pretty well. And what was funny to me, which I only realized later that actually kind of we switched from the Arduino community now to a modular synthesizer community. And while it, of course still mainly is sold as a independent or a standalone instrument, I think there is potential combining it with modules and integrating it even in a modular system.

Rick Reid  18:39  
Thierry, can you tell me about the CV output feature? I know that you've been working on some mods with that.

Thierry Frenkel  18:46  
After we had the hardware which was added in the v4 design, naturally, someone has to add the firmware parts to make use of this additional hardware. What I did was at first a lot of mathematics and calculus to get reasonable values out of the CV outputs corresponding to the current pitch and volume of the theremin. And they are, as you might perhaps know that it is different standards, especially for pitch CV. There is the Mook standard which is one volt per octave. And there is the Korg standard which is 800 hertz per volt. But I implemented both. You can select between both by recompiling the firmware with the different file switch, but the default value is the Moog setting, the one volt per octave. It has become in the meantime, much more common than the other standard. It's very difficult because it's a logarithmic standard to calculate in real time, logarithmic values on a small embedded microprocessor in Arduino style, so I had to do a lot of approximation, rounding, and all that to get a CV values out, but that works for the moment. The only glitch we have actually is when you go very low and playing beyond five octaves below the highest playable note. But I promise to fix that.

Rick Reid  20:14  
So the firmware is updatable, then fairly easily. 

Thierry Frenkel  20:18  
Yeah, you connect it to your computer USB port. And you can load the new source code from GitHub, and can compile it and upload it as if it were an Arduino processor.

Rick Reid  20:31  
I had great fun using the CV outputs. Last week, I got a cable that would connect it to my Moog Werkstatt. So I have one of the smallest theremins available in the world with one of the smallest synthesizers available in the world. And they worked really well together. It was a really good matchup.

Thierry Frenkel  20:48  
Thank you. It's because I tried to get very close to the Moog standard for the CVs. 

Rick Reid  20:55  
What sort of feedback have you received so far from people who bought the open Theremin version four?

Urs Gaudenz  21:00  
I was surprised like that it was well received. You know, whenever you do a new version, it's quite nerve wracking to see like if everything works if the production works if people like it, and if it also works on the user side or on the community side. And so I was happy for that. And then I also visited Coralie, Ehinger. She is kind of the lead user for the Open Theremin, the lead musician. I go visit her to test and discuss about like where the project should go. And she was really, I think, happy about the new implementation of the two control voltage outs. And I also had kind of her playing in mind because she, over the years developed a new way of actually playing the theremin by combining the classical theremin sound with new synthesizers, or with more synthesizers in the back. So instead of just using the theremin as a controller kind of enriching the traditional sound of the theremin with effects from the synthesizers. And so with the implementation that Thierry mentioned, it worked really well from the beginning. And so I'm really excited also, to see more people experimenting with this kind of playing like playing the audio combined with control voltage together.

Thierry Frenkel  22:04  
it just works and people are happy with it, because he did an excellent hardware design, which is stable, which is robust. So everybody is satisfied. We have users around the whole world from Europe, US, South America, even Asia. We have the guy that there in South Korea, who is posting almost every day a new video showing his progress on the Open Theremin v4. 

Rick Reid  22:29  
Oh, and remind us again, why you call it an Open Theremin. What does the Open part of that name mean?

Urs Gaudenz  22:35  
Well, still, now, of course, the version four as well as the earlier versions is completely open source. That means the hardware and the software is available on GitHub and on the website. So you can look at it, modify it, reprogram it, as Thierry mentioned, change or improve the code. On one side, this is called Open Theremin for this open source aspect. And on the other hand, also for the open community. As Thierry just mentioned, there is people around the world getting together around this project. And I think it inspires people to see the theremin in a new way to appropriate it, to make their own case, and now combine it maybe with modules from the modular synth community. And I think that's one part that I always liked about the Open Theremin project is this kind of community of people contributing and participating.

Rick Reid  23:22  
Now if somebody wants to purchase the Open Theremin v4 from the Gaudi Labs website, they're going to find that there are actually two versions of it available. What's the difference between the two? 

Urs Gaudenz  23:32  
One is more like the plain vanilla which I tried to keep the cost low. And the other is more like with USB-C cable and a nice stand that can change in height and more nice knobs and the cover for the back. So that's really just more convenience and aesthetics. But even with the cheaper version, if you get your own USB-C cable, you're ready to play, and antennas are included.

Rick Reid  23:52  
I was thrilled with the v3 and v4 is even better. So I'm really excited to hear how people around the world are going to be using your instrument over the months ahead.

Urs Gaudenz  24:03  
I think with Thierry we have some more ideas of what we could do in the future. 

Thierry Frenkel  24:07  
Let's say v4 is not the last one. Okay?

Urs Gaudenz  24:09  
Yeah, exactly. 

Rick Reid  24:10  
Thank you so much for being on Theremin 30. It's good to visit with you and, we'll see you again soon. To learn more about Urs and Thierry and about the new Open Theremin version 4 follow the links in this month show notes. Now let's finish this December episode with music from the Theremin Christmas album by Armen Ra here is the traditional French carole "O Holy Night."

Rick Reid  29:14  
And that puts a bow on another episode of the Theremin 30 podcast. I'm so grateful to Destroyer Creator with Aileen Adler, Thorwald Jorgensen, Stephen Hamm, and Armen Ra for sharing their wonderful music, and for my special guests Urs Gaudenz and Thierry Frenkel. Also a special thanks to the listeners who support the show with small one-time and monthly donations. I hope you have a safe and happy holiday season filled with lots of theremin music, and that we all have a very happy and healthy new year. I will see you in 2022.

David Brower  29:50  
You've been listening to the Theremin 30 podcast. Visit Theremin 30 on the web at