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https://github.com/rainbow-carrots/subsnake

experimental subtractive polysynth
https://github.com/rainbow-carrots/subsnake

adsr-envelope audio blit dsp njit oscilloscope polyblep python state-variable-filter subtractive-synthesis synthesizer virtual-analog

Last synced: 2 months ago
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experimental subtractive polysynth

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README 

          
# subsnake



subsnake is a polyphonic virtual analog subtractive synthesizer, written in python.



![](./subsnake/images/subsnake_dark.png)



### what's it do?

well, i'm glad you asked.

* it has 16 voices of polyphony

* it supports midi (input)

* it can save & load patches

* it can record, overdub, play, loop, & save audio



### what's in a voice?

* 3 sine, triangle, sawtooth, or pulse oscillators with pitch, detune, level & width controls | 2 algorithms ([BLIT](https://ccrma.stanford.edu/~stilti/papers/blit.pdf), [polyBLEP](https://mac.kaist.ac.kr/pubs/ValimakiPeknenNam-jasa2012.pdf))

* 1 state-variable filter with resonance, saturation & drive | 2 types (canonical Chamberlin, ZDF-solved Chamberlin)

* 2 ADSR envelopes - one for amplitude, one for filter frequency (with bipolar depth control) | .004-4s per stage

* 4 modulators - 2 LFOs, 2 AR envelopes, with dedicated assignable attenuverters for every parameter

    * LFO shapes: sine, triangle, ramp, sawtooth, square, sample & hold

        * 0.01-10Hz w/ controllable phase shift

    * env. modes: attack-release, attack-hold-release, loop (attack-release)

        * .01-1s per stage



there's also a stereo tape delay effect on the master bus (voice output + recorder), and a stereo audio recorder/looper with continuous overdubbing.



### what's the midi like?

* it supports device & channel selection, with note-on velocity (linear curve)

* cc's can be added & removed, and freely assigned to control any parameter

    * parameter updates are reflected visually, so the sliders & displays remain in sync with cc's

* gate on/off events use sample-accurate timing (works well with sequencers)



### how's the modulation?

* every parameter has a dedicated bipolar modulation control (the small knobs left of each slider)

* *right clicking* a knob changes the assigned modulator (and color)

    * none (disconnected) -> lfo1 -> lfo2 -> menv1 -> menv2 -> back to none

* *left clicking* a knob and dragging up/down will increase/decrease the modulation amount

* *double clicking* any knob will reset the modulation amount to 0.0 (centered)



### is there anything else?

* to reset a parameter, *double click* the parameter display (to the right of each slider)

* the keys A-' are mapped chromatically and can trigger note events (fixed velocity)

    * you can shift the pc keyboard octave range up/down using the +/- keys

* to switch between oscillator types (BLIT/polyBLEP), *right click* the oscillator title box

* to switch between filter types (Chamberlin/ZDF), *right click* the filter title box

* the filter & oscillator type selections are saved with the patch (& restored on load)

* the width parameter will have a different effect, depending on the selected shape:

    * sine: crossfades between silence at both extremes (center is full volume)

    * triangle: morphs the waveform from a sawtooth (w≈0.0), through a triangle (w=0.5), to a ramp (w≈1.0)

    * saw: crossfades between a saw & a second (free-running) saw at twice the fundamental (center is full fundamental)

    * pulse: bog-standard through-zero PWM

* each oscillator is paired with a stereo panner, allowing for precise placement (or modulation) across the stereo field

* filter key tracking & oscillator drift can be configured (per patch) via the synth settings menu

* the stereo delay can be made into a pitch-shifting delay (or pseudo-chorus) by modulating the time parameter with an LFO



### how can i play it?

* [v0.4.0](https://github.com/rainbow-carrots/subsnake/releases/tag/v0.4.0) is the latest build

* click on the version that corresponds to your platform to download the zip, extract, & run! if it doesn't open:

    * __on linux__: right click the file, go to *Properties* -> *Permissions*, and make sure "Allow executing file as program" is checked 

    * __on macos__: you'll need to [authorize the app](https://support.apple.com/guide/mac-help/open-a-mac-app-from-an-unknown-developer-mh40616/mac) when running it for the first time. go to *System Settings* -> *Privacy & Security*, scroll down to the bottom, and choose *Open anyway* (under *Security*)

    * __on windows__: click *More info* on the smartscreen popup and choose *Run anyway* 

* **note**: on first load, it may take 1-2 minutes for the initial numba compilation step to complete.

* **note**: this project is in active development. though I test every build prior to release, you may still encounter bugs.



### what else is planned?

* save & auto-restore midi settings (channel, cc's, parameter mappings)

* recorder settings panel:

    * adjustable loop start/end points

    * input level control (currently fixed)

    * playback speed control

* synth settings panel:

    * pc keyboard velocity control

    * voice stacking & spread settings

* oscillators:

    * [LP-BLIT](https://www.dafx.de/paper-archive/2017/papers/DAFx17_paper_59.pdf) implementation

    * VOSIM implementation

    * anti-aliased wavetable oscillator

* modulators:

    * shape-dependent secondary control (currently sets phase only)

        * phase for sine, saw & ramp

        * width for square & triangle

        * slew for sample & hold

    * third LFO & modulation envelope

    * make LFOs anti-aliased (for audio-rate mod.)

    * additional LFO modes:

        * reset phase on gate

        * key pitch tracking (w/ ratio)

    * increase max. LFO rate to audio range

    * add audio oscillators as mod sources

* effects:

    * stereo delay

        * add ping pong & dampening parameters

    * stereo chorus

    * algorithmic reverb

    * combine effects into single stack

* mixer:

    * noise submodule

* isorhythmic pattern generator/sequencer

* Lissajous display mode for scope

* more patches :3