SpessaSynth logo

A powerful SF2/DLS/MIDI JavaScript library for the browsers, based on spessasynth_core. This is a WebAudioAPI wrapper for the spessasynth_core library.

v4.0.0 TypeScript Update is here! The NPM package now contains type declarations for easier developing! Read about breaking changes here

It allows you to:

Play MIDI files using SF2/SF3/DLS files!
Read and write MIDI files!
Write SF2/SF3 files!
Convert DLS to SF2! (and back!)
and more!

TIP:

Looking for a bare JS version that works without WebAudioAPI? Try spessasynth_core!

Project site (consider giving it a star!)

Made with spessasynth_lib

Documentation

SpessaSynth Project index

spessasynth_core - SF2/DLS/MIDI library
spessasynth_lib (you are here) - spessasynth_core wrapper optimized for browsers and WebAudioAPI
SpessaSynth - online/local MIDI player/editor application
SpessaFont - online SF2/DLS editor

Current Features

All the features of spessasynth_core!

On top of that...

Fully typed: Faster development and IDE auto-completion!
Modular design: Easy integration into other projects (load what you need)
Detailed documentation: With examples!
Easy to Use: Basic setup is just two lines of code!
No external dependencies: Just spessasynth_core!
Reverb and chorus support: customizable and can be used standalone!
Export audio files using OfflineAudioContext!
AudioWorklet synthesizer:
- Runs in a separate thread for maximum performance!
- Does not stop playing even when the main thread is frozen!
- Supported by all modern browsers!
Web Worker synthesizer:
- Synthesize directly in the Web Worker!
- Direct audio engine access!
- Export audio automatically in the worker!
- Avoids Chromium Audio Bugs!
High-performance mode: Play Rush E! note: may kill your browser ;)

Special Thanks

FluidSynth - for the source code that helped implement functionality and fixes
Polyphone - for the sound bank testing and editing tool
Meltysynth - for the initial low-pass filter implementation
RecordingBlogs - for detailed explanations on MIDI messages
stbvorbis.js - for the Vorbis decoder
fflate - for the MIT DEFLATE implementation
tsup - for the TypeScript bundler
foo_midi - for useful resources on XMF file format
Falcosoft - for help with the RMIDI format
Christian Collins - for various bug reports regarding the synthesizer
And You! - for checking out this project. I hope you like it :)

Basic example: play a single note

import { WorkletSynthesizer } from "spessasynth_lib"

// SF2, SF3, SFOGG and DLS files are all supported!
const sfont = await (await fetch("soundfont.sf3")).arrayBuffer();
const ctx = new AudioContext();
// make sure you copied the worklet processor!
await ctx.audioWorklet.addModule("./spessasynth_processor.min.js");
const synth = new WorkletSynthesizer(ctx);
await synth.soundBankManager.addSoundBank(sfont, "main");
await synth.isReady;
document.getElementById("button").onclick = async () =>
{
    await ctx.resume();
    synth.programChange(0, 48); // strings ensemble
    synth.noteOn(0, 52, 127);
}

License

SoundFont® is a registered trademark of Creative Technology Ltd.

Package detail

spessasynth_lib

readme