jMax is a visual programming environment for building interactive real-time musical and multimedia applications by allowing the user to interactively design dataflow circuits. The basic data types that can go through are integers, symbols, lists, etc. It is an event-driven system and has been used for MIDI processing. A second part of the system (DSP) allows a continuous signal to flow through a circuit, which is most useful for PCM sound (ie. microphone, sound files, etc.). The system is extensible by using shared libraries, you may add data processor types, data types, GUI elements, device types, and more. Data processors may also be designed as circuits and reused.
Cecilia is a graphic user interface for the sound synthesis and sound processing package CSound. Cecilia enables the user to quickly build graphic interfaces with sliders and curves to control CSound intruments. It is also an editor to CSound with syntax highlighting and a built-in reference.
FMS is a tool to create all kinds of sounds from scratch. You can play any sound (sine, triangular, vowels, etc.) with any property settings (frequency, volume, balance, sweep, etc.) and modulations thereof. It also features tools to save sounds, play .MUS music, graphically display sounds, and make real noise.
din is a software musical instrument and audio synthesizer. Bezier curves are used to draw and sculpt waveforms, create gating and modulation (FM and AM) patterns, and create delay feedback and volume patterns. You can also create an unlimited number of drones and sculpt their waveforms. It uses JACK to output audio, and supports MIDI, OSC and IRC bot for input. din can be extended and customized with Tcl scripts.