Kid3 tagger can edit the ID3v1 tags and all ID3v2 frames in MP3 files and the tags in Ogg/Vorbis and FLAC files in an efficient way. It is easy to convert between ID3v1 and ID3v2, set the tags of multiple files to the same values and generate the tags from the file name or vice versa. Import is possible from freedb.org, MusicBrainz, and other sources of track data.
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.
Ecasound is a software package designed for multitrack audio processing. It can be used for simple tasks like audio playback, recording, and format conversions, as well as for multitrack effect processing, mixing, recording and signal recycling. It supports a wide range of audio inputs, outputs, and effect algorithms. Effects and audio objects can be combined in various ways, and their parameters can be controlled by operator objects like oscillators and MIDI-CCs. A versatile console-mode user interface is included in the package.
cutmp3 is a small command line MP3 editor. It lets you select sections of an MP3 interactively or via a timetable and save them to separate files without quality loss. Silence and ID3 tag searching are also possible. For playback it uses mpg123. The program works with VBR files and files bigger than 2GB. There is also a simple frontend for it, called xcutmp3.
MuseScore lets you notate and compose music easily with your keyboard, your mouse, or a MIDI keyboard. You can print beautifully engraved sheet music or export it as PDF or PNG. You can play your score, transpose it, and save it as audio or MIDI file. MuseScore also supports MusicXML to let you share your composition with other scorewriters. MuseScore is often advertised as a cost effective alternative for Sibelius and Finale.