libxmp is a module player library which supports many mainstream and obscure module formats, including Protracker MOD, Scream Tracker III S3M, and Impulse Tracker IT. Possible applications for libxmp include standalone module players, module player plugins for other players, module information extractors, background music replayers for games and other applications, module-to-mp3 converters, etc.
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.