Algoscore is a graphical environment for algorithmic composition, where music is constructed directly in an interactive graphical score. The result is output to MIDI and CSound. Graphical objects are placed in a timeline and connected together. Some objects are fully dependent on user data, while some are generative and reacts on input from other objects. It is highly customizable and extensible with the Nasal scripting language. It has a non-realtime perspective where the composer can relate freely to time and construct the composition outside of time. This makes AlgoScore more like a traditional sequencer in this regard, but a graphical algorithmic sequencer with powerful and flexible scripting capabilities.
Audacity is a cross-platform multitrack audio editor. It allows you to record sounds directly or to import Ogg, WAV, AIFF, AU, IRCAM, or MP3 files. It features a few simple effects, all of the editing features you should need, and unlimited undo. The audio I/O uses PortAudio, which fully supports OSS, Mac OS X CoreAudio, and Windows WMME, and can be compiled with support for ALSA and Jack.
AudioSlicer is a Cocoa GUI application that finds all silences in an audio file and allows you to split it into several smaller audio files and to name/tag them properly. While most other tools split automatically according to certain criteria, AudioSlicer shows you all silences within a certain range of duration. You can then listen and decide whether you want to split there. The splitting is done without loss; there is no decoding and re-encoding of audio data.
Canorus is a cross-platform music score editor. It supports an unlimited number and length of staffs, polyphony, MIDI playback of written notes, chord markings, lyrics, and a number of import and export filters to many formats like MIDI, MusicXML, ABC Music, MUP, PMX, MusiXTeX, and LilyPond. It features multiple viewports of the same score, scripting support, score source view, and a fast and intuitive UI. It is based on Qt4, uses CMake as a project management tool, swig for scripting/macros integration (primary script languages are Ruby and Python), and the cross platform rtmidi library for MIDI playback. It is the official successor to NoteEdit.
DAP is a comprehensive audio sample editing and processing suite. It currently supports AIFF and AIFF-C audio files, 8 or 16 bit resolution, and 1, 2 or 4 channels of audio data. The package offers comprehensive editing, playback, and recording facilities including full time stretch resampling, manual data editing, and a reasonably complete DSP processing suite.