The EMS Synthi VCS3 Project

Hey there! It’s finally finished! Some of you might have already seen some of my progress in the past few weeks, in case you haven’t, I’ll “quickly” explain what I’ve been up to. I will cover as much as I can so it’s going to be a long post. The links to patches and videos will be at the bottom in case it’s a bit too much too read :slight_smile:

So I have been doing a lot of research on the inner workings of the EMS Synthi VCS3 as I was building a VCV version of this awesome machine. After seeing some videos of people jamming on a VCS3, but also on the Synthi AKS, I felt inspired to reproduce the patchbay that is at the heart of both of these and several more EMS products, feeling it would be a very inspirational bit of gear. So I found some patch matrices in the plugin browser, plugged some modules together and wow! It certainly delivered! But that little endeavour quickly turned into wanting to recreate as many aspects of the Synthi as I can inside VCV!

The first few versions were already nice sound effect machines and I learned much about a lot of things in the process, got familiarized with the matrix and the ease with which sounds are created, but often I kept thinking “This is probably not exactly what you could do on a Synthi…”, turning knobs that actually wouldn’t be available, making connections that wouldn’t be possible, so I started looking online to see if I could find some specifications.

As I was reading the original manual I noticed at least one probably very crucial part of the puzzle: the waveshapes. Every oscillator has a shape knob that on oscillator 1 lets you dial in two very distinct variations of a sine, a shape that I found to be most easily created using Phase Distortion Synthesis available in Bidoo’s TiARE oscillator. Then there is pulse width modulation on the squares and an up and a down ramp on either side of the triangles on oscillators 2 and 3. For this I again chose Bidoo’s TiARE since these came the closest in recreating the ramp-triangle-ramp change without resorting to wavetables.

Then there is the volume of the oscillators, which is probably also crucial to get right. Standard volume for any given oscillator seemed to be around 10V peak to peak, whereas the Synthi has levels ranging from 3V (Sine, Triangle) to 6V (Ramp) peak to peak. I imagine this has a great influence on how it makes its sounds, and in my tries I have found a great deal of variation to be had in adjusting these levels. In the patches I included an INIT patch with the volumes adjusted to the specifications given in the manual, which greatly changes how it reacts to just about everything.

Which brings me to tuning. I really wanted to get the frequency ranges on the oscillators spot on, but this proved to be more difficult than I thought, mainly because the Nysthi tuners I used didn’t really give accurate measurements under 1 Hz. At the moment I am quite certain about the upper limits (500 Hz for the LFO/Oscillator 3, 10 kHz for Oscillators 1 and 2). I measured the LFO lower limit and it had a cycle of about 23,71 seconds which amounts to a lowest frequency on the dial of 0.04 Hz which is unfortunately still too fast but it’s the closest I could get for now without messing with the upper limit.

It doesn’t stop there though, the oscillators are calibrated to 0,32V/Oct, which means that the usual 1V/Oct is more than 3 times too much, although I have the feeling this could be compensated by not adjusting all the volume levels to Synthi specs. So for now I didn’t adjust the voltage sensitivity, something I might try in the volume adjusted INIT patch.

For the filter I chose the Vult Lateralus, after comparing it among others to the Laika by Lindenberg Research and another diode ladder filter by Autinn, Lateralus came out sounding the fullest and most versatile. I do not know exactly if it sounds anything like the original filter but it feels authentic, the response and drive act like I expect them to.

For the patching matrix I took the one from Strum for its simplicity and clarity. I tried the Bogaudio Matrix88 but although it has attenuation possibilities at the matrix (plus attenuverting possibilities which will probably come in handy in some of my other matrix synth project ideas), I found it difficult to see what knobs I had in use. I posted a request for color lit knobs on the Bogaudio GitHub and he replied that he would think about it, so fingers crossed! Another candidate was Bidoo’s ACnE, which has snapshots for instantly recalling different patches, and color changing knobs, but it has the inputs and outputs flipped which was too confusing for now. For the matrix layout I chose the version of the VCs3 that has all oscillators available at the matrix. I found some pictures of a matrix with Output Channel 1 and 2 as the first to rows, which I tried and it has nice possibilities, but I prefer the tonal flexibility of having all the waveforms at my disposal. In some example patches I connected some available outputs to the external channel inputs I included which was a way on the original to get extra control voltages double the amplitude due to the channel input amplification circuit.

One other thing I wanted to capture was the layout and workflow of the original, so I chose to put all the modules responsible for the sound to the side and replace them with an array of knobs by RJModules controlling just the actual available parameters. This does give an ease of mind as soon as you get to know what every knob does, but it also makes for a heavy patch, at least for my computer :slight_smile:

I’m probably missing some more small details, but also feel this is as close as I’m gonna get for now and I would like to start doing other stuff with VCV again. Trying to get it ready for uploading I keep finding myself tweaking parameters and twisting the knobs to see what otherworldly sounds it can create. A good test for me was to see if the example patches from the manual would sound anything like their descriptions; with some of them I got a really good result, some of them don’t really sound like the description but are fun patches nonetheless. Below are a few videos and a list with patches:

-INIT Patch

EMS VCS3 GUI INIT Patch.vcv (133.7 KB)

-INIT Patch with adjusted volume levels

EMS VCS3 GUI INIT Patch Accurate Volumes.vcv (133.7 KB)

-Original Manual Example Patches 1-15 (excluding 11 and 12)

EMS VCS3 GUI Manual Example Patch 1.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 2.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 3.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 4.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 5.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 6.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 7.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 8.vcv (133.9 KB)

EMS VCS3 GUI Manual Example Patch 9.vcv (133.9 KB)

EMS VCS3 GUI Manual Example Patch 10.vcv (133.8 KB)

EMS VCS3 GUI Manual Example Patch 10v2.vcv (133.7 KB)

EMS VCS3 GUI Manual Example Patch 13.vcv (133.9 KB)

EMS VCS3 GUI Manual Example Patch 14.vcv (133.9 KB)

EMS VCS3 GUI Manual Example Patch 15.vcv (134.1 KB)

-Pink Floyd - On the Run

EMS VCS3 GUI On the Run.vcv (149.3 KB)

-Runny Arpeggio

EMS VCS3 GUI Runny Arpeggio.vcv (134.0 KB)


EMS VCS3 GUI Bass Drone.vcv (133.1 KB)

EMS VCS3 GUI Chordy Drone.vcv (133.8 KB)

EMS VCS3 GUI Dripping Fifth Drone.vcv (134.0 KB)

EMS VCS3 GUI Ripping Stereo Lead.vcv (133.8 KB)

EMS VCS3 GUI Stereo Octave Sirens.vcv (133.9 KB)

EMS VCS3 GUI Stereo Octaverb Drone.vcv (133.7 KB)

EMS VCS3 GUI Tritone Phasing Feedback Verb Drone.vcv (133.9 KB)

EMS VCS3 GUI Vocal Flute.vcv (133.6 KB)


EMS VCS3 GUI Beatmachine 2.vcv (138.3 KB)

EMS VCS3 GUI Beatmachine.vcv (138.2 KB)

EMS VCS3 GUI Kick n Bass.vcv (133.8 KB)

-SFX Machine

EMS VCS3 GUI SFX Machine.vcv (133.7 KB)

-Computer Keyboard

EMS VCS3 GUI Computer Keyboard.vcv (134.8 KB)

For tips on how to use, it’s best to refer to the original manual (

I would love to see what you do with it, feel free to share videos or updates to the patch in this thread, that should make for a fun collection of bleepy sounds! If you have any suggestions on what could be improved, please let me know!



thanks for that fantastic work !

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That’s rather brilliant - you’ve done a great job in reproducing the look as well. Just one thing missing though: when the spring reverb was active one could play the cabinet like a percussion instrument…

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Thanks! You are right, I forgot about the reverb, that’s a great idea to try and see how I can recreate that! The reverb has a second input still available, some kind of impulse to excite it should do the trick :slight_smile:

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I always kept a pair of drumsticks next to mine!

the nysthi::complexDAHD can easily imitate the EMS Synthi/VCS3 trapezoid

both as SIGNAL (becoming an Audible Oscillator at high frequency of looping) and ENVELOPE shaper

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Thanks for the tip! I will check it out when I try to adjust the envelope times to correspond to the original specifications!

I just realized I didn’t mention in my description that I used the Nysthi Vectormixer for the joystick, which was the best option with the smoothest output, comparing it for instance to the JWModules XY Pad.

adding info about the complexDAHD the main difference is the DELAY phase: is BEFORE in the DAHD and after in the TRAPEZOID but in a loop is unnoticeable

I think I found a way to replicate this functionality, check this out:

EMS VCS3 GUI INIT Patch (Reverb Percussion).vcv (142.6 KB)

EMS VCS3 GUI Reverb Percussion.vcv (142.6 KB)


if you find somewhere the IR file for an original (cheesy japanese) SpringReverb in the synthis, you can use nysthi::convolvzilla

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Ah yes I have used Convolvzilla before, I’m sure it would do the trick but I didn’t try it in this project yet since my computer already has a lot of trouble playing this patch. I’m getting a better graphics card soon, that should solve most of my trouble…

I read that the Befaco Reverb also has an IR loaded though, might be nice to be able to change which IR it loads, although it is a dedicated spring reverb that does what it’s designed to do :slight_smile:

Nice. It would be simple enough to midi it up to a set of hardware pads…

Okay I was just trying out Convolvzilla again, really amazing plugin, it doesn’t seem to be as heavy on the cpu as I remember, I checked again and the Befaco Spring Reverb is asking a lot more. It does seem to clip quite easily though… I’m gonna have to experiment a bit more :slight_smile:

I haven’t tried these rack patches,but I actually own a vcs3, and I will give them a try. I used it a lot on my first record and did a lot of patching of drum machines through it. I actually used a sound it was making that was an accident, which was the spring reverb picking up the vibration from the fans in my computer combined with mysterious signal crosstalk in the pin matrix.

One thing you won’t get in a vcvrack emulation is the effect of the unbuffered pin matrix. If you use the same cv in two inputs, the load on the source changes and the pitch sags. And if you route two signals to the same input, they’ll also affect any other input they’re connected to.


I’m really looking forward to hear your opinion on how it compares to your own VCS3! I can imagine there are a lot of things that don’t react like the original so I hope you can give some more suggestions on what could be improved!

I’ve actually thought about how to incorporate little quirks like crosstalk between connections or some other kind of dirtier signal path, but couldn’t figure out how to just yet. In some example patches I also patched in a Vult Trummor 2 which was a lot of fun, and I’m sure there are several ways of recreating the computer fan accident :slight_smile:

If you could find the time, I would love to see some videos from an experienced VCS3 user trying the patch, even better of course if the two could be compared side by side! For instance I’d be really curious to hear what some of the manual example patches would sound like on the original, to see if I got close :slight_smile:

I can’t promise I’ll have time to do everything you asked but I’ll try!

I imagine that you can approximate the mechanical resonance of a spring reverb by simply feeding it a sample of whatever mechanical sound you want to resonate. The thing about a spring reverb is that it works by literally vibrating a string; there’s a transducer physically moving the spring. The difference between picking up mechanical vibrations of the cabinate and the direct input signal is mostly one of amplitude, though no doubt the physical peculiarities of the cabinet itself might have a subtle effect.

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Honestly I had a hard time understanding your patch, though it made some very vcs3 sounds if I twiddled knobs randomly.

I thin it’s a good candidate for a Plugin developer as it’s mostly assembling readily available sub components. @synthi I hear the Putney calling you!

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Do you really think ? :slight_smile: about 2 years ago I did an experiment in EMS style, but was too expensive in terms of time, so I abandoned the idea

but probably I can redo charging $10 per module :slight_smile:


Okay, that surprises me! Can you maybe explain what was so hard to understand?

Things I didn’t understand:

  1. What all the knobs were. Label modules would help.
  2. What the 4 pin matrices did.

I’m not being critical of your work at all. I have a hard time understanding other people’s patches, including my own from 6 months ago.