A modular synthesizer for the command line written in golang.
- Install and setup Go
- Clone the repository
git clone git@github.com:iljarotar/synth.git- Install
cd synth
make build
cp bin/synth /usr/local/bin # or somewhere else in your PATHRun
synth examples/sequencer.yamlto listen to an example.
Patches for the modular synthesizer are provided in yaml format.
A patch contains configurations for all modules that you want the synthesizer to play.
When you modify and save a patch during playback the synthesizer will reload the file.
Since changing a parameter like volume or frequency by a large amount too quickly results in a clipping noise, most modules allow configuring a fade parameter that controls how long it takes for the module's parameters to transition from the previous value to the new one.
Such a fade-over is not only useful to avoid clipping sounds but can also be utilised to create slow transitions in the music.
Say, for example, you want to slowly fade in one module while slowly fading out another.
You can add a fade parameter to the mixer that controls both modules' volumes—e.g. fade: 5 for 5 seconds—and change the new module's volume to a positive value and the other one's to 0.
Then save the file and the transition will start.
This section explains all available modules and provides example configurations. For more examples see the examples directory.
Each module must have a unique name across all modules.
This name is used as a reference in other modules, e.g. when a module is used as a CV or modulator.
Each module outputs values in the interval [-1, 1].
Additionally, all parameters of a module are limited not to extend the reasonable ranges for each specific parameter, e.g. an oscillator's frequency will never exceed 20,000Hz.
Such limitations make the outcome of a configuration more predictable.
Those modules whose main purpose is to provide CV values for other modules only output values between 0 and 1.
If a module is provided with a CV its static value is ignored.
For example, if you pass a CV to an oscillator this CV will provide the oscillator's frequency and the statically assigned frequency will be ignored.
When mapping a CV-provider's output to a parameter, only positive values are considered.
So a value in the interval [0, 1] is mapped to the respective parameter's range.
For example, a sequencer will output values in the range [0, 1] and those values will be mapped to an oscillator's frequency range [0, 20000] if the sequencer is used as a CV for that oscillator.
If a module is provided with a modulator it will modulate a parameter around its static or CV-provided value.
For example, a mixer with a gain of 0.5 and a sine wave as a modulator will output a tremolo around the gain value of 0.5.
For example, an oscillator's frequency is in the range [0, 20000].
A modulator that outputs values in the entire possible range of [-1, 1] will modulate the oscillator's frequency in the entire range [0, 20000].
To control the amount of modulation you must send the modulator through a mixer and attenuate its gain.
The following yaml file provides examples and explanations for all configuration parameters.
# my-patch.yaml
# main volume control
# range [0, 1]
vol: 1
# name of the module to output
out: name-of-main-module
# delay effects
delays:
# the unique module name to be used as a reference in other modules
delay:
# delay time in milliseconds in range [0, 5000]
time: 100
# gain of delayed signal in range [0, 1]
gain: 0.25
# name of the module to run through the delay
in: name-of-input-module
# cv for `mix`
cv: name-of-cv-module
# modulator for `mix`
mod: name-of-modulator
# fade controls the transition length in seconds
# affected parameter is `gain`
fade: 2
# adsr envelopes
# output values in range [0, 1]
envelopes:
# the unique module name to be used as a reference in other modules
envelope:
# attack length in seconds
# range [1e-15, 3600]
attack: 0.1
# decay length in seconds
# range [1e-15, 3600]
decay: 0.05
# release length in seconds
# range [1e-15, 3600]
release: 2
# peak level targeted during the attack phase
# range [0, 1]
peak: 1
# sustain level
# range [0, 1]
level: 0.75
# name of the module to use as a gate signal
# when gate output changes from negative or zero to positive the envelope is triggered
# while gate is positive the attack, decay or sustain phases are active
# when gate output changes from positive to negative or zero the envelope is released
gate: name-of-gate-module
# fade controls the transition length in seconds
# affected parameters are `attack`, `decay`, `release`, `peak` and `level`
fade: 2
# filters of type low pass, high pass or band pass
filters:
# the unique module name to be used as a reference in other modules
filter:
# one of LowPass, HighPass, BandPass
type: BandPass
# critical frequency
# range [0, 20000]
freq: 500
# band width in case of type BandPass
# ignored for other types
width: 50
# cv for `freq`
cv: name-of-cv
# modulator for `freq`
mod: name-of-modulator
# name of the module whose output will be filtered
in: name-of-input-module
# fade controls the transition length in seconds
# affected parameters are `freq` and `width`
fade: 2
# gates can be used as gates for envelopes or sequencers or as triggers for samplers.
gates:
# the unique module name to be used as a reference in other modules
gate:
# beats per minute controls the tempo of the gate signal
bpm: 260
# cv for `bpm`
cv: name-of-cv
# modulator for `bpm`
mod: name-of-modulator
# binary signal
# each negative or zero value will be mapped to `-1`, each positive to `1`
signal: [1, 0, 0, 1, 0, 1, 1, 0, 1, 0]
# provides an initial offset to the signal
# count starts at 0
index: 4
# fade controls the transition length in seconds
# affected parameter is `bpm`
fade: 2
# mixers combine outputs of multiple modules and control their output levels
mixers:
# the unique module name to be used as a reference in other modules
mixer:
# gain in range [0, 1]
gain: 0.5
# cv for `gain`
cv: name-of-cv
# modulator for `gain`
mod: name-of-modulator
# mapping of module names to their corresponding gain levels
# these gain levels can be in the range [0, 1000]
# the output will be limited not to exceed the range [-1, 1]
in:
name-of-first-module: 0.5
name-of-second-module: 0.25
# fade controls the transition length in seconds
# affected parameters are `gain` as well as all input modules' gain levels
fade: 2
# noise modules simple output random values
noises:
# the unique module name to be used as a reference in other modules
# a noise module doesn't have any parameters to configure, so pass an empty object `{}`
noise: {}
# oscillators output basic wave forms like sine waves, triangles, etc.
oscillators:
# the unique module name to be used as a reference in other modules
oscillator:
# one of Sine, Square, Triangle, Sawtooth, ReverseSawtooth
type: Sine
# frequency in range `[0, 20000]`
freq: 440
# cv for `freq`
cv: name-of-cv
# modulator for `freq`
mod: name-of-mod
# static phase shift in percent of one period
# range `[-1, 1]`
phase: 0.75
# fade controls the transition length in seconds
# affected parameters are `freq` and `phase`
fade: 2
# pan modules are used to add stereo balance
pans:
# the unique module name to be used as a reference in other modules
pan:
# specifies how big a portion of the signal is output through the left and right channels
# range `[1-, 1]`
# a value of `-1` places the signal completely to the left, `1` places it to the right
pan: -0.5
# name of the module whose output should be stereo balanced
in: name-of-input-module
# modulator for `pan`
mod: name-of-mod
# fade controls the transition length in seconds
# affected parameter is `pan`
fade: 2
# sample and hold modules
samplers:
# the unique module name to be used as a reference in other modules
sampler:
# name of the module that is being sampled
in: name-of-input-module
# name of the trigger module
# when the trigger's output value changes from negative of zero to positive a new sample is taken from the input modules output
trigger: name-of-trigger-module
# sequencers can be combined with oscillators or wavetables to create melodic sequences
# output values in range [0, 1]
sequencers:
# the unique module name to be used as a reference in other modules
sequencer:
# a sequence of notes in scientific pitch notation
# flats are denoted by `b`, sharps by `#`
# a note is separated from its octave by an underscore
# minimum octave is 0, maximum is 10
sequence: ["a_4", "eb_3", "c#_5"]
# when the trigger's value changes from negative or zero to positive the next note in the sequence is triggered
trigger: name-of-trigger-module
# base pitch from which to calculate all other frequencies
pitch: 440
# transpose the whole sequence by any number of semitones
# range `[-24, 24]`
transpose: -4
# if `true` the notes in the sequence will be played in random order
randomize: true
# provides an initial offset to the sequence
# count starts at 0
index: 2
# pass any values to a wavetable to create arbitrary signals
wavetables:
# the unique module name to be used as a reference in other modules
wavetable:
# frequency in range `[0, 20000]`
# specifies how many times per second the entire signal given in the `signal` field will be played
freq: 440
# cv for `freq`
cv: name-of-cv
# modulator for `freq`
mod: name-of-mod
# an arbitrary signal
# the signal can have any length
signal: [-1, 0, 0.25, -0.3, 0.8, 1]
# fade controls the transition length in seconds
# affected parameter is `freq`
fade: 2On first run, synth will create a synth/config.yaml file in your default config directory.
Modify this file to adjust the configuration.
Run synth -h to see where this file was placed.
You can also override single parameters via command line flags.