Synthpy

A simple CLI square synth with midi connectivity written in Python using sounddevice and mido.

Devon Fox and Matt Stevenson 2022

Mac/Linux/Windows Build Instructions

Make sure the latest version of Python is installed.

1. First upgrade pip and setuptools:

pip install --upgrade pip setuptools

2. Then make sure the ALSA development dependencies are installed:

MAC/WINDOWS USERS: can skip this step

sudo apt-get install -y python3-dev libasound2-dev

3. Install Numpy (math library)

pip install numpy

4. Install Sounddevice (audio Library)

pip install sounddevice

5. Install Mido midi library

pip install mido

6. Install Python-rtmidi for use of midi ports

pip install python-rtmidi

Windows Build Instructions

In addition to the above, windows users will need a midi loopback tool in order to connect a midi keyboard to the synth. The one provided below works well and is free:

loopMidi: https://www.tobias-erichsen.de/software/loopmidi.html

Also, you need to specify the --port arg to be 99 when using loopMidi on windows.

To run the program, in the same directory, type the following in the terminal:

python3 synthpy.py

You can customize many aspects of the resulting audio (or dare I say music) with the following commands:

Without entering arguments, the defaults will be used. Give command --h to access help menu

Ex. --wave square

• allows us to choose the waveform of the synthesizer (Default: square)

Ex. --buffer 256

• set the sample buffer size Warning: raising can increase latency (Default: 256)

Ex. --attack 0.05

• set the amp envelope attack time (in seconds)' (Default: 0.05)

Ex. --decay 0.05

• set the amp envelope decay time (in seconds)' (Default: 0.05)

Ex. --sustain 0.5

• set the amp envelope sustain level (between 0 and 1) (Default: 1.0)

Ex. --release 0.25

• set the amp envelope decay time (in seconds) (Default: 0.25)

Ex. --port 0

• select which midi port to receive from (Default: 0)

Ex. --portlist False

• list all available midi ports, and select which one to connect to at startup - --port can be used instead if you already know portnumber or want to startup headlessly (Default: False)

Ex. --effect toaster

• enable the toaster effect

to note: sustain will be held if using a sustain pedal via midi