Signal processing

Hi!! I have a question that I have tried to solve looking out on the internet and I haven’t found relevant information. Could anyone explain to me which basic tools of signal processing are used (generally) in the modular synth?

I think the core processing mainly consists of running the modules in the correct order, as determined by the cable connections. Graph theory may be used for that.

All the actual interesting sound processing happens in the modules. To implement those, one will need knowledge about DSP, like how to implement filters, oscillators, delay lines and so on. This is not to say that the modular patching system itself is trivial to implement. It gets especially complicated if one wants that support parallel multithreaded processing on multiple CPU cores.

Thank you very much for your answer! Maybe I was not very specific, but I meant tools like filters, Fourier transforms… I am finishing Telecomunication Engineering and I wanted to understand what’s behind the modules in the meening of Signal Processing

You should look for resources on audio DSP in general, most of it will be applicable for implementing VCV Rack modules too. (With some differences in some details. For example VST plugins process the audio as buffers, Rack modules process the signals sample by sample.)

The open source Rack modules are of course a great source of information how things can be implemented.

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To answer that you have to answer “What modules are generally used in modular synths?” If your answer is VCOs, VCFs, VCAs, sequencers, etc then figure out what DSP goes into making those.

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Thanks Andrew!! Do you know where can I find this module’s code? I amb not able to find it

What module?

Any, for example a VCA, or an LFO, or whichever

You can get to the source from within Rack. Right click a module and go to the context menu item labelled plugin, here a drop down will appear with different options, among them will be manual, donate, source etc.

If a plugin doesn’t have a source link it is either not filled in or is closed source, if the former the source might be available in the repository of the developer on GitHub which can most likely be got from the plugin manger or by searching for the developer on GitHub.


There are thousands of modules out there from hundreds of devlopers. They are all going to be different! One small but interesting subset is the “Fundamental” modules that come with VCV. They are here: