LOI is a realtime sound processing tool. You can use it as a software guitar pedal or a voice distorter or for any other realtime sound processing purposes you can think of. It uses LADSPA sound processing plugins. The core is written in C, the frontend is written in Python with GTK+ bindings, so it's easy to maintain and extend.
It is far from being complete, but if you meet the requirements, you can try it, it is already working and you may actually like it. See my TODO list for some things I'd like to implement in the future. However, I'm quite busy right now so it may take several months till I do some work on the LOI again. Requirements
The program runs under linux only and uses the OSS sound drivers (other drivers are planned). It works in 44100Hz, 16bit mono full duplex mode only, your soundcard must support this(most modern soundcards do). You should have at least 200MHz pentium with 32 MB RAM for the program to be useful. You must have python and pygtk installed. Under debian, install package named python-gtk2. LOI is tested with GTK2 version 2.6. Furthermore, you need libsndfile for reading and writing audio files. In debian, this package is called libsndfile1-dev.