Beast is a digital synthesizer and music creation system, released as Free Software under the GNU LGPL-2.1+. It has support for Linux Audio Plugins (LADSPA), multi-track editing, unlimited undo, real-time synthesis, MIDI and various audio formats like WAV, AIFF, Vorbis, Soundfont 2, Gus Patch, FLAC and MP3 files, 32bit audio rendering, full duplex support, multi-core audio rendering, SIMD utilisation, precise timing at sample granularity, FFT spectrograms and MIDI automation. The project is translated into a variety of languages.

beast.testbit.eu

github.com/tim-janik/beast