wx12Ton helps one to work with music involving twelve-note series. In particular, it displays the 48 forms of a twelve-note series, and tests series for tonal phrases. In addition, wx12Ton allows the user to list the complete set of all twelve-note series which satisfy certain criteria.
libmls is a library that can be used to measure the frequency response of a loudspeaker or a room using your computer and an ordinary soundcard. It can perform both MLS (Maximum Length Sequence) and Sinus sweep measurements. It supports ALSA, OSS, and the sound system used in Windows.
Noiseclock is a console-based program designed to summarize the amount of time needed to play a given sound file or directory of files. Output can be any combination of days, hours, minutes, and seconds. It supports any of the sound formats supported by TagLib, which are currently MP3, OGG, and FLAC compressed files.
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.
sauditor is a sample auditor that is intended to be simple and quick to use. It allows you to quickly and easily search for the sample you want. It features a curses interface, with no mousing required, and a toggleable X spectrum analyzer. The spectrum analyzer lets you see the frequencies present in your samples, which is handy if you want an idea of how much "space" the samples take up in the mix. It uses Jack for output, which allows you to connect filters to the output.