Mixxx is Free DJ software that gives you everything you need
An old-school polyphonic synthesizer
Turn your PC into a very advanced MediaCenter/HTPC
The X Jack Video Monitor
Specialized sound synthesizer with Byzantine Church music scales
Trains quickly score reading and piano playing (MIDI-keyboard)
Hybrid Virtual Synthesizer
it's a video player, also works for music and pictures
Polyphonic synthesizer LV2 plugin
Music Player Daemon SACD/DVD-A ISO decoder plugins
A music tracker software for Windows.
Very simple MIDI Player of JSON files
Tool to remotely activate Text-To-Speech (TTS) on a server
A c++ public domain audio output class
GUI to work with abc notation