PHP Voice (formerly known as PHP VXML) contain four classes that assist in developing voice application using PHP. It supports Speech Synthesis Markup Language 1.0, Speech Recognition Grammar Specification 1.0, Voice Browser Call Control: CCXML 1.0, and Voice Extensible Markup Language (VoiceXML) 2.0.
Scheme Note is a Scheme-like music file format and MIDI conversion tool. It takes a text file, which is a representation of a song, loosely tied to a MIDI-like event structure, and outputs a corresponding MIDI file. It is hand-editable for simple songs, and should be very easy to parse for a GUI.
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.
Virtual Sound provides unlimited effects and modulation for sophisticated audio generation, with unique instrument simulation capabilities to craft your own unique soundscapes. All effects are parametrized and their parameters may be controlled through the outputs of other effects, through samples, or through special modulators. Instrument simulation is based on recursively-linked filter networks. Actual instruments can also be simulated through the statistical learning library incorporated in VSound.
Soundmosaic constructs an approximation of one sound out of small pieces of other sounds. The soundmosaic algorithm is: split the target file up into equal-sized segments, or "tiles". For each tile in the target file, find the closest match in the source files, and replace the target tile with the tile from the source files.
SynthTest is a somewhat simple application for OS X that allows you to pick a MIDI source, a MusicDevice AudioUnit, and an Effect or MusicEffect AudioUnit to play with. You can open an edit window for both the synth and effect. If they do not have a custom edit GUI, the generic editor view will be used. SynthTest has a reference implementation of preset support for Audio Units. It is primarily intended to be used by Audio Unit developers for testing purposes (the source is available), although it can be great fun to play with all by itself. It is complete enough to be used for live performances.
Hydrogen is a simple real-time Drum machine/sequencer. It features a graphical user interface based on Qt, a sample-based audio engine, Jack/ALSA/OSS/PortAudio and Export to disk audio drivers, ALSA MIDI input, ability to import/export XML-based song and drumkit files, 192 ticks per pattern, 16 voices with volume, mute, solo, ADSR, and pan capabilities, and import of samples in wave, au, and aiff format.
Javasynth is a Java-based system for creating (rather experimental) modular audio systems called sound modules. This allows synthesizers of some kind to be assembled in a modular fashion using oscillators, amplifiers, envelopes, filters, and other components familiar to those that have worked with hardware synthesizers. It includes a separated synth engine and a Swing user interface for building sound modules.
Open Sound World (OSW) is a scalable, extensible programming environment that allows musicians, sound designers, and researchers to process sound in response to expressive real-time control. It combines a familiar visual patching paradigm with solid programming language features such as a strong type system and hierarchical name spaces. OSW also includes an intuitive model for specifying new components using a graphical interface and high-level C++ expressions, making it easy to develop and share new music and signal processing algorithms.