Wavesurfer.js
Navigable waveform built on Web Audio and Canvas
Teoria
A JavaScript music theory framework.
Vexflow
A JavaScript library for rendering music notation and guitar tablature.
Midi Writer Js
♬ JavaScript library providing an API for programmatically generating expressive multi-track MIDI files in browser and Node.
Speak.js
Text-to-Speech in JavaScript using eSpeak
Jsmediatags
Media Tags Reader (ID3, MP4, FLAC)
Tuna
An audio effects library for Web Audio, made by www.dinahmoe.com
Howler.js
Javascript audio library for the modern web.
Pizzicato
Library to simplify the way you create and manipulate sounds with the Web Audio API.
Webaudio.js
web audio library for games
Waud
Web Audio Library
Flocking
Flocking - Creative audio synthesis for the Web
Sound JS
A Javascript library for working with Audio. Features a simple interface as the front end to multiple audio APIs via a plugin model. Currently supports HTML5 Audio & Flash.
Midi.js
Making life easy to create a MIDI-app on the web. Includes a library to program synesthesia into your app for memory recognition or for creating trippy effects. Convert soundfonts for Guitar, Bass, Drums, ect. into code that can be read by the browser. Supports multiple simultaneous instruments and perfect timing.
Pedalboard.js
Open source JavaScript framework for developing audio effects for guitars using the Web Audio API.
Buzz
Buzz is a small but powerful Javascript library that allows you to easily take advantage of the new HTML5 audio element. It tries to degrade gracefully on non-modern browsers.
Timbre.js
JavaScript library for objective sound programming