MrsWatson is a commandline audio plugin host. It takes one or more plugins, sends an audio signal to them for processing, and saves the resulting output. Although the plugins think they are running in realtime, processing is actually done offline (this is not the same as the "offline" processing in VST terminology). This makes MrsWatson ideal for developing or debugging plugins, or processing audio on a server.
Lyra is a front-end to the Music Player Daemon (MPD). Based loosely on the Creative Media Source software, it has the aim of supporting large collections of albums and artists. Other interesting features are the implementation of a local cache of the music library using an SQLite database, increased speed, and flexibility. In addition, Lyra supports integration with the Last.fm service, which includes "Scrobbling" and album cover art.
annoyme is a program that plays a sound effect every time you hit a key on your keyboard to give you the feeling you are using a real typewriter. This can be used to impress colleagues with your typing skills or just for sentimental reasons. It supports various sound input methods, as well as multiple output libraries like ALSA or AO. Most importantly, it is also possible to add more sound themes. Currently, only input for XEvIE (on an X Server) is supported.
Scalpel is an audio editor for Linux. It aims to provide a simple-to-use and easy-to-extend audio editor. Scalpel still has some rough edges but is quite usable. Scalpel uses PyGTK for the user interface, Numpy for the internal processing, ALSA for the audio playing, and libsndfile for reading and writing files. A minimal part of the code is written in Cython for better performance.
DromeAudio is a small audio manipulation and playback library. It features a simple API for loading, generating, processing, and playing audio. Some of its features include loading and saving WAV sounds, loading Ogg Vorbis sounds, audio mixing/playback, and dynamic audio processing effects such as pitch shifting and echo.
MilkyTracker is a multi-platform music application for creating .MOD and .XM module files. It attempts to recreate the module replay and user experience of the popular DOS program FastTracker II, with special playback modes available for improved Amiga ProTracker 2/3 compatibility.