Latest release: https://github.com/Birch-san/juicysfplugin/releases

Demo track: mp3, FLAC, FLAC+compressor

What

juicysfplugin is a macOS audio plugin for playing MIDI music through a soundfont synthesizer.

It's well-suited for making videogame music. If you have a soundfont of your favourite game, you can write your own melodies with its instruments.

JUCE is the framework for making audio plugins.
fluidsynth is the soundfont synthesizer.

Mode 1: standalone application

juicysfplugin.app is a standalone application, for playing around.

You can plugin your hardware MIDI keyboard, or play with the software MIDI keyboard. Or route MIDI messages into it from a virtual MIDI controller (e.g. the macOS IAC Bus).

Mode 2: audio plugin

juicysfplugin audio plugins are provided: VST, VST3, AU, AUv3.
This means you can host it inside your DAW (e.g. GarageBand, FL Studio Mac, Sibelius…) to record the sounds you make.

Why

I couldn't find a free, easy-to-use macOS audio plugin for making music with soundfonts.

Install

Latest release: https://github.com/Birch-san/juicysfplugin/releases

Download Release.tar.xz, open it to unzip.

Release contains:

juicysfplugin.app  # standalone application, for playing around
juicysfplugin.component  # AU plugin
juicysfplugin.vst  # VST plugin
juicysfplugin.vst3  # VST3 plugin

To install plugins, move them to the following folder:

juicysfplugin.component -> ~/Library/Audio/Plug-Ins/Components/juicysfplugin.component
juicysfplugin.vst -> ~/Library/Audio/Plug-Ins/VST/juicysfplugin.vst
juicysfplugin.vst3 -> ~/Library/Audio/Plug-Ins/VST3/juicysfplugin.vst3

Launch

Now, you may do one of the following:

• Open the standalone juicysfplugin.app
• Load the AU/VST/VST3 into your favourite DAW (e.g. GarageBand, FL Studio)

Usage

You must drag-and-drop a soundfont into the file picker.

Here's some soundfonts to get you started:

• MuseScore's recommended soundfonts (includes MIT, GPL, other licenses)
• FlameStudios' GPL-licensed guitar soundfonts

I'll refrain from recommending specific General MIDI or videogame soundfonts, since the licensing and provenance are often unclear.

Keybindings

Gain keyboard focus by clicking the plugin's keyboard.

• Up-down arrow keys to switch preset.
• Left-right to switch bank.

ASCII -> MIDI keybinding is the same as FL Studio's:

Using the standalone .app

Generally the .app will Just Work™, but if your audio setup is more bespoke, then you'll need to configure.
Ignore the yellow warning about feedback. There is no feedback loop (because no audio is input).

Options > Audio/MIDI settings

Set Output to Built-In Output

Or any output device that you can hear audio through.

Input audio device doesn't matter. We only use MIDI as input.

Building from source

Install XCode and XCode command line tools. Accept terms.

Ensure brew and libfluidsynth are installed:

# --with-libsndfile is optional; it adds support for SF3 format
brew install fluidsynth --with-libsndfile

Install JUCE 5.3 in /Applications.
We expect to find JUCE headers in /Applications/JUCE/modules.

(Optional) To target VST3, install Steinberg VST3 Audio Plug-Ins SDK.
We expect to find a folder ~/SDKs/VST_SDK/VST3_SDK.

(Optional) Install IntelliJ AppCode if you prefer it to XCode.

Open juicysfplugin/Builds/MacOSX/juicysfplugin.xcodeproj in XCode (or IntelliJ AppCode).

Build & run the "juicysfplugin - Standalone Plugin" target.

Testing VST/AU plugins inside an audio plugin host

You'll notice that the schemes for [VST, VST3, AU, AUv3] targets are configured such that "Run" launches the executable AudioPluginHost.app. This lets you run the audio plugin as though it were hosted inside a DAW.

I recommend building (e.g. with XCode) the simple Audio Plugin Host that comes with JUCE Framework:

/Applications/JUCE/extras/AudioPluginHost/Builds/MacOSX/AudioPluginHost.xcodeproj

Then symlink /Applications/JUCE/AudioPluginHost.app to the built AudioPluginHost.app (because that's where I told the Run configuration to look for AudioPluginHost.app):

ln -sf /Applications/JUCE/extras/AudioPluginHost/Builds/MacOSX/build/Debug/AudioPluginHost.app /Applications/JUCE/AudioPluginHost.app

Dependency versions

Known working with:

• macOS High Sierra 10.13
• XCode 9.3.1
• JUCE Framework 5.3
• VST3 Audio Plug-Ins SDK 3.6.9
• fluidsynth 1.1.11

Making portable releases

Follow the steps in Building from source to output a product to the build folder.

The .app, .vst (and so on) that you build will only work on a computer that has brew fluidsynth installed.

If you want to build a truly portable release, you'll need to bundle libfluidsynth and all its dependencies into your product.

cd juicysfplugin/Builds/MacOSX
# first check that you have a Release or Debug product in the `build` directory

# bundles `juicysfplugin/lib` libs into the products you created,
# relinks your executables to use their bundled libs
./relink-build-for-distribution.sh

# follows symlinks, archives Release and Debug folders as tar.xz
./archive-for-distribution.sh

Note: Release and Debug flavors both output targets [VST, VST3, AU] to the same location: ~/Library/Audio/Plug-Ins/$TARGET/juicysfplugin.$EXT.
Whichever flavor you built most recently, wins.

The way I provide archives of both build flavors is by archiving one, building next flavor, then archiving that (i.e. I build serially, not parallel).
But probably people only care about the Release flavor anyway.

Licenses

Overall, juicysfplugin is GPLv3.

See licenses for all libraries and frameworks.

Questions

Windows/Linux/Android/iOS version?

No big barriers. The source code and all its dependencies are cross-platform. The main friction is setting up a dev environment, and learning how to link dynamic libraries on that OS (i.e. we need to link to libfluidsynth).

Some thoughts that come to mind:

• Bundling libraries portably is far easier on Windows than on macOS
  • Just throw a dll next to the executable
  • .NET assembly binding can be debugged using fuslogvw
• Windows already has plenty of free, nice soundfont plugins
• It's probably pretty hard to bundle fluidsynth into mobile apps
• Bundling would be easier if I used static linking
• Static linking is hard