SignalFlow

SignalFlow is a sound synthesis framework designed for clear and concise expression of complex musical ideas. It has an extensive Python API, for fluid audio experimentation in iPython/Jupyter, with its core written in portable, hardware-accelerated C++11.

SignalFlow is in beta status. Interfaces may be subject to change.

Example

from signalflow import *

#--------------------------------------------------------------------------------
# An AudioGraph is made up of a network of interconnected Nodes, which generate
# and process audio. 
#--------------------------------------------------------------------------------
graph = AudioGraph()

#--------------------------------------------------------------------------------
# Passing an array of frequencies creates a stereo output.
#--------------------------------------------------------------------------------
sine = SineOscillator([440, 880])

#--------------------------------------------------------------------------------
# Simple attack/sustain/release envelope with linear curves.
#--------------------------------------------------------------------------------
env = ASREnvelope(0.01, 0.1, 0.5)

#--------------------------------------------------------------------------------
# Use standard arithmetic operations to combine signals. When a multi-channel 
# signal is multiplied by a mono signal, the mono signal is auto-upmixed.
#--------------------------------------------------------------------------------
output = sine * env

#--------------------------------------------------------------------------------
# Connect the output to the graph, and begin playback.
#--------------------------------------------------------------------------------
output.play()
graph.wait()

Installation

SignalFlow requires Python 3.8 or above, and supports macOS, Linux (x86_64), Raspberry Pi (3+), and Windows (64-bit).

In a nutshell, SignalFlow can be installed with pip: pip3 install signalflow.

For a complete walkthrough on setting up your system with Python and SignalFlow, see Installing SignalFlow.

Examples

Several example scripts are provided in examples.

To download the examples folder:

import signalflow_examples
signalflow_examples.download_examples()

Documentation

In-depth documentation, including a reference guide to each of the Node classes, can be found at signalflow.dev.

Node class library

The following Node classes are currently included with the base distribution:

Category	Classes
Analysis	CrossCorrelate, NearestNeighbour, OnsetDetector, VampAnalysis, YinPitchTracker, ZeroCrossingRate
Buffer	BeatCutter, BufferLooper, BufferPlayer, BufferRecorder, FeedbackBufferReader, FeedbackBufferWriter, HistoryBufferWriter, SegmentPlayer
Buffer: Granulation	SegmentedGranulator, Granulator
Control	MouseX, MouseY, MouseDown
Envelope	Accumulator, ADSREnvelope, ASREnvelope, DetectSilence, Envelope, Line, RectangularEnvelope
FFT	FFTBufferPlayer, FFTContinuousPhaseVocoder, FFTFindPeaks, FFTMagnitudePhaseArray, FFTNode, FFTOpNode, FFTPhaseVocoder, FFT, IFFT
Fft: Features	FFTSpectralCentroid, FFTSpectralFlatness, FFTSpectralFlux
Fft: Processors	FFTContrast, FFTConvolve, FFTCrossFade, FFTLFO, FFTLPF, FFTNoiseGate, FFTRandomPhase, FFTScaleMagnitudes, FFTTonality, FFTTransform
Operators	Add, AmplitudeToDecibels, DecibelsToAmplitude, Bus, ChannelArray, ChannelCrossfade, ChannelMixer, ChannelOffset, ChannelSelect, Equal, NotEqual, GreaterThan, GreaterThanOrEqual, LessThan, LessThanOrEqual, Modulo, Abs, If, Divide, FrequencyToMidiNote, MidiNoteToFrequency, Multiply, Pow, RoundToScale, Round, ScaleLinExp, ScaleLinLin, SelectInput, Subtract, Sum, TimeShift, Sin, Cos, Tan, Tanh
Oscillators	Constant, Impulse, LFO, SawLFO, SawOscillator, SineLFO, SineOscillator, SquareLFO, SquareOscillator, TriangleLFO, TriangleOscillator, Wavetable, Wavetable2D
Physical	Maraca
Processors	Clip, Fold, Smooth, WetDry, Wrap
Processors: Delays	AllpassDelay, CombDelay, OneTapDelay, Stutter
Processors: Distortion	Resample, SampleAndHold, Squiz, WaveShaper
Processors: Dynamics	Compressor, Gate, Maximiser, RMS
Processors: Filters	BiquadFilter, DCFilter, EQ, MoogVCF, SVFilter
Processors: Panning	AzimuthPanner, ChannelPanner, SpatialPanner, StereoBalance, StereoPanner, StereoWidth
Processors: Reverb	FeedbackDelayNetwork
Sequencing	BlockCounter, ClockDivider, Counter, Euclidean, FlipFlop, ImpulseSequence, Index, Latch, Sequence, TriggerMult, TriggerRoundRobin
Stochastic	Logistic, PinkNoise, RandomBrownian, RandomChoice, RandomCoin, RandomExponentialDist, RandomExponential, RandomGaussian, RandomImpulseSequence, RandomImpulse, RandomUniform, StochasticNode, WhiteNoise

Contributors

Thanks to the following contributors:

• Greg White (@gregwht): Examples, documentation and testing
• Arthur Carabott (@acarabott), Tim Murray-Browne (@timmb): Windows support
• Dan Stowell (@danstowell): Build improvements
• Marc Fargas (@telenieko): Generous donation of the signalflow pypi namespace
• Ed Gillett: Generous donation of Linux build machine
• Sid Gudka: Generous donation of Windows build machine

Support

Thanks to the following supporters and sponsors:

• The Python Software Foundation for funding development of learning materials
• JetBrains for providing the IDEs used to develop SignalFlow

License

Use of the SignalFlow library with a Python interpreter, script or notebook is licensed under the free and permissive MIT License.

Use of SignalFlow or its components outside of a Python environment (for example, embedded within a binary object) is subject to a separate agreement. Please contact the author to discuss.