A Tiny Node Modular Synth

This is a very basic modular synth I made that's configured with yaml files. You can call it via:

npm start path/to/file.yml

There's some examples in the examples folder, which you can try out via:

npm start examples/chords.yml

Moreover, there's a way to draw the node graph, if you'd like:

npm test examples/chords.yml

This can be helpful for building your own things and testing them out.

Configuring the Synth

The synth is configured with a YAML file, that is passed as the first argument to the script. It consists of three sections: nodes, values, and connections.

Nodes

nodes allows you declare nodes and assign them names for later use. An example section might look something like this

nodes:
  osc1: Oscillator
  osc2: Oscillator
  chord: Sequencer
  lfo: Oscillator

You can then reference those nodes by name in later sections

Values

The values section allows you to assign constant values to properties of a node. For instance, an oscillator can be created to have a constant frequency

values:
  osc1.carrier: 220
  osc2.carrier: 440

Connections

The connections section allows you to provide the dynamic portions of the synthesizer and connect nodes you've previously declared. For instance, you can connect the above sequencer to the first oscillator, then connect that oscillator to the speaker

connections:
    chord: osc1.carrier
    os1: speaker.input

The examples folder also provides some sample configuration files for creating various sounds.

Available Node Types

There are multiple node types available, and all of them have a predefined set of inputs and a single output.

Oscillator

The Oscillator node provides a simple sine or square oscillator. Setting carrier defines it's frequency, and amplitude the amplitude. waveform is a string value set to either "sine" or "square" which will change the waveform.

LowPassFilter

The LowPassFilter implements a basic low pass filter. It has two parameters: filterWidth a number which, when higher, lowers the cutoff frequency and input, the input to filter.

Noise

The noise node implements random noise, with no inputs.

Sequencer

The sequencer node will loop over an array of values periodically and emit those as values. Its first input parameter is sequence, an array of values to emit. Its second is length which denotes how long to stay on a given value before moving to the next one.

Adder

The adder node adds its two inputs input1 and input2 and provides the sum as it's output

Multiplier

The multiplier node multiplies its two inputs input1 and input2 and provides the sum as it's output

Envelope

The envelope node provides an ADSR Envelope. You can set a couple of inputs:

• attack the attack time of the envelope
• decay the decay time of the envelope
• sustain the sustain level of the envelope
• release the release time of the envelope
• trigger should be a 1 or a 0 triggering the envelope to start. For instance, if the envelope is silenced, setting trigger to 1 will start the envelope. It will attack, then decay, and wait at sustain until a trigger of 0 is encountered, upon which it will because the release process.

Installation Help

npm install may fail on your machine, due to sound library configuration required by the speaker module. In short, you may have to change you npm install to something like npm install --mpg123-backend=openal or npm install --mpg123-backend=coreaudio depending or your system.