Overview

This repository contains Python MIDI synthesizers which can be played in real-time, e.g. from a USB MIDI keyboard, a MIDI file, an on-screen MIDI keyboard such as VMPK or the included midi_keyboard.py. Audio demos are available at the PySynth homepage.

There are also various other MIDI-related scripts here, some of them requiring PyGame.

Synthesizers

They all require PyAudio (for audio output) and mido (for MIDI event handling):

• multi_synth.py: 8-note polyphonic additive synthesizer
• multi_wave.py: 12-note polyphonic wavetable synthesizer
• epiano.py: 8-note polyphonic DX7 FM e-piano synthesizer (ported from PySynth E; code based on multi_synth.py)
• midi_synth.py: simple monophonic additive synthesizer

Default polyphony settings are fairly low to make sure the synths can run on older hardware, but can be changed in the scripts if desired.

Multi_synth.py and midi_synth.py produce a piano-like timbre using three sine waves like PySynth A and an exponential decay like PySynth B, so they sound very similar to PySynth A and B. Multi_wave.py on the other hand loads a wavetable with a guitar-like sound by default.

PyGame-based scripts

• midi_keyboard.py: an on-screen MIDI keyboard which can be used to play the synths or to show incoming MIDI notes from other sources
• falling_notes.py: piano trainer with falling MIDI notes. Press Space to pause, press F or S to go faster/slower.
• scale_explorer.py: show different musical scales on a piano keyboard; use cursor keys to navigate.

Other scripts

• midi_play.py: play a MIDI file; can be used to play back a MIDI file to these synthesizers
• midi_play_slow.py: play a MIDI file slowly
• pitch_range.py: show pitch range of a MIDI file (highest/lowest notes), so you can see if a piece is playable on your MIDI controller or needs a bigger octave range.
• studio.py: a simple MIDI recording studio. By default, MIDI program 0 is where you play and where all notes are recorded and program 1 is for control mode. Playing a C in control mode shows info, playing D replays all notes in memory, and playing E saves as a MIDI file to the current directory.

Wavetables

The wavetables directory contains some other wavetables for multi_wave.py. There also some Python scripts in that directory that demonstrate how to create wavetables.

It is also possible to convert wavetables from other synthesizers. Often these are in 32-bit floating point format, so they need to be exported as 16-bit integer WAVs in Audacity. The number of samples per waveform needs to be set in multi_wave.py. Also, the volume should be set low enough so that multi_wave.py does not crash even when many notes are playing simultaneously.

In case of audio problems

If you hear crackling audio from these scripts, you might want to

• quit other applications, especially web browsers.
• increase audio buffer size (BSIZE) in the scripts or reduce maximum polyphony (MAXPOLY).
• make sure you are running a recent Python version, because Python performance tends to improve with each release.

Credits

• 2010_mavericks_competition.jpg: photo by Shalom Jacobovitz; derivative work: Brocken Inaglory, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons