Soundbench is high-quality GPL-licensed software synthesizer written in C++/Qt that is meant to work across all major platforms (though especially most common Linux distributions).
Soundbench follows a development philosophy that emphasizes getting everything stable before adding new features.
Soundbench is meant to be usable by anyone who wishes to produce music, whether they are hobbyists, professional musicians, or experienced sound designers.
The program is currently in Beta...