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Yet Another Synthesizer Engine

YASE is a modular digital audio synthesis and processing library designed specifically to teach digital audio synthesis. You can use it to make sounds, sequences, and effects. You can connect MIDI devices and sound sources.

There are literally dozens of tools similar to YASE -- like Faust, the STK, and SuperCollider. You should probably use one of those. They are more established, have broader user bases, and tons of contributed modules and examples. Those other systems likely have higher performance and fewer bugs than YASE.

That said, YASE is pretty fun and easy. In case you are interested, it is:

  • Written in modern(ish) C++
  • Fast and scalable
  • Easy to use and extend
  • Modular, just like your signal processing diagrams
  • Open source (Gnu Public License)

More information about YASE can be found at


Here's an example of a basic YASE program that makes a neat sound. There are more examples in the examples directory of this repository.

#include "yase.hh"

using namespace yase;

int main(int argc, char * argv[]) {

    Sine sine1, sine2;
    Audio audio;
    Container synth;
    sine1.set_input("frequency", 440);
    sine2.set_input("frequency", 441);


    return 0; 


The first three lines of the main function declare some modules: two sine wave sources, an audio interface, and a container to put everything into. The next block sets the frequency inputs of the two sine waves to be 440 Hz and 441 Hz respectively. The connect statements connect the output signals of the sine waves to the left and right inputs of the audio interface. Finally, the run statement runs the program until the user presses Ctrl-C. The result is a pleasing sound. Try it!

One thing to notice about modules is that their inputs and outputs are named by strings during set up. This makes working with I/O easy and straightforward. When you make your own modules, you can add as many inputs and outputs as you would like with whatever names make sense for your use case. If you use the wrong name, YASE gives you an easy to understand error message. Once all the connections are made and the container (named synth in this case) is run, YASE uses integer indices to the I/O so there is no string matching at run time. These two setup and run phases are common to all YASE programs.


To date, Yase has been developed on MacOS 11.6.1. The following are required:

  • git, g++, and make, part of the MacOS Development Tools.
  • Brew, for installing things:
  • PortAudio, which can be installed with `brew install portaudio``
  • RtMidi:, which can be installed with brew install rtmidi
  • Google Test: which can be installed with `brew install googletest``
  • Niels Lohman's JSON library, which can be installed with brew install nlohmann-json
  • FFTW, which can be installed with brew install fftw
  • AudioFile, which can be installed with brew --prefix adamstark-audiofile
  • To make the docs, you'll need doxygen and graphviz: brew install doxygen graphviz

On some Macs things are installed in strange places. Doing the following helps the linker work right.

export PATH="/usr/bin:$PATH"

Once all the prerequisites are installed, get the code and compile it

git clone
cd yase

Assuming no errors, you should be able to hear sound if you run