Band.js : An interface for the Web Audio API that supports rhythms, multiple instruments, repeating sections, and complex time signatures.
meSpeak.js : meSpeak.js (modulary enhanced speak.js) is a 100% client-side JavaScript text-to-speech library
Flocking : Flocking is a JavaScript audio synthesis framework designed for artists and musicians who are building creative and experimental Web-based sound proje...
SoundManager 2 : Using HTML5 and Flash, SoundManager 2 provides reliable cross-platform audio under a single JavaScript API.
Essentia : Open-source library and tools for audio and music analysis, description and synthesis
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 library to provide a vocal synthesizer for the web.