FluidSynth - software real-time MIDI synthesizer
FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications and has become widely used. FluidSynth itself does not have a graphical user interface, but thanks to its powerful API, several applications use it and it has even found its way into embedded systems and some mobile applications.
Qsynth - GUI for FluidSynth.
