Working with default fluidsynth
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
Here's some royalty-free soundfonts to get you started:
http://www.flamestudios.org/free/Soundfonts#fsibanezac
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Avoided CoreAudio deadlock by deregistering all of fluidsynth's audio drivers.
This is better than the previous workaround, which required a bespoke build of fluidsynth (i.e. compiled without CoreAudio support).