Wikipedia
Ecasound
Ecasound is a hard-disk recording and audio processing tool for Unix-like computer operating systems including Linux, Mac OS X, and FreeBSD.
Ecasound allows flexible interconnection of audio inputs, files, outputs, and effects algorithms, realtime-controllable by builtin oscillators, MIDI, or interprocess communication via GUI front-end. Ecasound supports JACK and LADSPA effects plug-ins.
The team leader is Kai Vehmanen, with dozens of contributors. Kai joined the project in 1995, when it was called wavstat, a simple DSP utility running under OS/2. Available under the GNU General Public License, Ecasound is free software.