VSTPLANET : VST Plugins Free - Virtual instruments and effects
Essentia : Open-source library and tools for audio and music analysis, description and synthesis
meSing.js : meSing.js is a JavaScript singing synthesis library that uses the Web Audio API's DSP capabilities in conjunction with the meSpeak.js speech synthesis...
librosa : librosa is a python package for music and audio analysis. It provides the building blocks necessary to create music information retrieval systems.
Cecilia : Cecilia is an audio signal processing environment aimed at sound designers. Cecilia mangles sound in ways unheard of. Cecilia lets you create your own...
ixi audio is an experimental project concerned with the creation of digital musical instruments and environments for generative music.