Open-Source Virtual Eurorack Modular Synthesizer, VCV Rack, Now Available

At Knobcon 2017, developers launched VCV Rack – an open-source virtual Eurorack modular synthesizer that’s available as a free beta download for Linux, Mac & WIndows.

The system features software versions of some of the most popular Eurorack modules, including virtual versions of modules from Mutable Instruments, Befaco and Synthesis Technology. Many of the module are direct ports of the code from the hardware modules.

The system is based around VCV Rack – a virtual Eurorack case. You can add modules, edit parameters, and save/load patches. Patches are created by making connections with  your mouse. The basic rack comes with 8 analog-modeling modules.

You can perform by connecting a MIDI keyboard controller or sequencer to VCV Rack. There are also plans for a VST/AU version.

In the Rack, control voltages and audio signals are equivalent, so you can modulate parameters with sonic-range VCOs to create customizable FM synths or chaotic wave-shaping oscillators.

If you already own a hardware modular synthesizer, you can use VCV Rack to expand your system virtually by connecting your hardware via an audio interface that supports CV signals or a CV-MIDI-CV interface module.

You can expand your rack by downloading virtual versions of some popular Eurorack modules:

Audible Instruments – Based on the Mutable Instruments Eurorack modules, Audible Instruments gives you a collection of complex sound generators, modulation sources, sound modifiers, and signal utilities. All modules which are based on real digital modules are ports of their original source code, so generated signals are faithful to the hardware.

E-Series – The E-Series plugin features a port of Synthesis Technology’s E340 Cloud Generator, a VCO capable of fat, chaotic, and swarming sound with up to eight combined saw and sine oscillators detunable with a spread parameter and filtered noise.

Befaco – Includes Befaco’s EvenVCO, A*B+C, Spring Reverb, Mixer, Slew Limiter, and Dual Attenuverter modules, with DSP measured from hardware. Virtual versions of Befaco’s Rampage, VC ADSR, and Hexa VCA are also in the works.

Pricing and Availability

VCV Rack is available to download now for free, and is available for Linux, Mac & Windows. Source code is also available at Github.

If you’ve used VCV Rack, leave a comment and share your thoughts on it!

43 thoughts on “Open-Source Virtual Eurorack Modular Synthesizer, VCV Rack, Now Available

  1. I think when you don’t know where to start with a real modular, this a good introduction. Can help to choose the modules that you Need. For free. Nice.

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  2. I downloaded on a Mac Pro and started using. I found that the module selection menu is flashing and jittering crazily, making it very difficult to select modules. Is anyone else having this problem? Also, the manual is virtually nonexistent right now. But it looks promising!

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    1. I have the same for the pulldown menu for the soundcard. Practically makes the audio interface module unusable. That’s on Win10 with a Motu connected.

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  3. I get a mono signal from either left or right speaker. I cant seem to find a way to send the mono to both left & right outputs. Are you supposed to have an interface which allows duplicating mono? Maybe i’m missing something.

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    1. I thought there would be either a splitter or multi-destination patching, but there seems to be neither. Odd.

      Apart from that, though, it’s a very impressive system.

      Update: There is in fact a splitter, just not in the base modules. It’s part of the Audible Instruments pack.

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  4. it seems very good when it works. but currently it has lots of issues – the flickery menu problem I got around by clicking wildly until I managed to select an audio interface. I made a nice simple patch and saved it, reloaded the app and loaded the patch … lots of blank modules (no graphics) with the patchpoints offset to the left.
    Well, I’ll try it again when it’s a little more stable. If it can get off this bumpy ground it will be a good product.

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  5. I downloaded it and everything works fine. However, I have to agree with @ted that with a nonexistent manual it’s a little frustrating. I’m a Supercollider user (and use a Prophet) so even if I have an idea of what should go where its not always so easy/obvious. But if you’ve never had anything like this, you’d be well advised to watch a few ‘modular synth’ video tutorials on YouTube.

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  6. Worked fine for me on Sierra. Had a little play, no problems as of yet. Sounds good and covers a reasonable amount of ground – excellent for a free product.

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  7. I cannot seem to get the adsr module to work with a vca. I tried both the audible instruments and the default one and it doesn’t seem to work. I use ableton live as source with loop midi on windows 10. The notes trigger but they don’t decay to zero regardless of the decay setting.

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  8. @ BJD: Yes operating fine on a core i7 on Win 10 pro 1703 – build 15063.540 here with Rack v0.3.0.
    Using it with ASIO driver to Focusrite Scarlett 2i4 and a Novation midi controller. No launch or operational errors. No graphical glitches in panels or menus I’ve noted. Using current nVidia drivers on a GTX 760.

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  9. I have been looking for basicaly this same synth for a long time
    my only concern is that there is no vst mode and as i can tell no way to midi map
    im sure it will come
    great work

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  10. You all are going to think I’m n idiot, but I can’t manage to get a sound out of this thing due to idiocy. My sound is fine, no screen problems, but no sound, no matter what I choose. Thinking about trying ASIO out of my KORE but I’m lazy. Anyone else having this issue? Any tips?

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    1. First thing’s first: Make sure the audible element of your signal is patched through to the output. Do this by following your patch cables from sound source to amplifier, making sure all the connections are where they should be and make sense. If everything is patched properly yet still no sound, I’d assume the issue is with your computer (drivers?) or speakers.

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    2. Most basic way: right click, then add the audio interface moldule and a VCO module(such as Fundamental VCO) and drag a cable from any waveform labeled (sine,etc) output directly to any one of the audio interface inputs. Get freaky from there.

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      1. If i got something for free no one complains easily, but if the code is transferred for 100% this is a miss. 😉 Also alternate Firmwares like Parasites, Bees In The Trees and Kammerl should be there by a click.
        Is there a workaround for alternate modes? Some buttons are yet not there…..

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  11. The folks on Github were very helpful getting me up and running yesterday. I would use that as a resource if you are having issues.

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  12. Works well apart from audio drop down lacks the sound quality of both softube and reaktor, but takes up less CPU, and still souunds great, very good fun on par with oscillator, it looks great will be interested to see where this goes very much looking forward to the vst version, thanks for the gift

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  13. weird, on Macos 10.12.6 Sierra when i only add and audio interface and choose build in audio, processor usage goes to 79% (version 0.0)

    brilliant software of free btw.

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    1. This is noted kn the website that it runs like this but as soon as you route an oscillator it pulls it back down.

      In no programmer but it says something about an infinite loop

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  14. Awesone synth! Absolutely on par with softube and reaktor blocks!! Well, the mutables are 100% clones, how that could sound bad!?
    I hope to have all major bugs resolved in next version, looks very promising!

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  15. Making progress on my Mac Pro running Sierra. v0.3.1 has lost the jittery menu. But now when I connect Audio Interface to my mac core audio output, CPU usage blasts up to 93%!!

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  16. Help! Missing graphics (knobs etc.) on Windows 7 64 …. Ive seen the ‘save patch in same directory as exe’ solutions but they don’t work. Rack already starts up with missing graphics…

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