Songbird is a real-time spatial audio encoding library for WebAudio applications. It allows web developers to dynamically spatially-encode streaming audio content into ambisonics signal, which is rendered using Omnitone to output stereo sound, for realistic 3D audio.
Gibber is a live coding environment for the web browser, using the Gibberish.js audio engine, the CodeMirror code editor library and wrapping Three.js for 3d graphics and shader support. It also features mapping abstractions and a server/database backend for collaborative live coding.
Tone.js is an extensive Web Audio framework to create interactive music. It offers features like transport and timing, prebuilt synths/effects and DSP modules to build your own synthesizers, effects, and complex control signals.
Flocking is an audio synthesis framework to build creative and experimental sound projects. Its goal is to promote a community-minded approach to instrument design and composition. In Flocking, unit generators and synths are specified as JSON, making it easy to save and share your synthesis algorithms.
Wad is a library to create, transform and play back sounds. It offers a lot of functionalities usually found in DAWs (digital audio workstations): synthesis, effects, panning, pitch detection, MIDI I/O, etc.
Timbre.js is a graph-based audio processing and synthesizing library. It can be used to create sounds from oscillators and play them back with filtering and effects.
The node-midi library is a wrapper for the RtMidi C++ library. It provides realtime MIDI I/O on Linux (ALSA & Jack), Macintosh OS X (CoreMidi) and Windows (Multimedia).
This Node.js module abstracts the command-line usage of SoX so you can create complex SoX commands and run them with ease. For example, you will be able to play concatenate and trim audio files, transcode audio streams, apply a wide variety of effects, etc.