Volimiter is a free and open source faceless background application (daemon) which limits the system's sound volume.
It uses CoreAudio API to get notified about output volume changes and, whenever the volume exceeds a certain limit, it will restore it to the said limit.
HOW TO USE:
· You supply the only argument to volimiter, a desired fraction of maximum output volume, for example: volimiter 0.25. This will limit the default output device's volume to 0.25 of the maximum value. If you run volimiter without an argument, it will use current output volume as the limit.
· To stop volume limiting simply kill volimiter: killall volimiter
NOTE: This product is distributed as arsware under the terms of GNU General Public License. If you find it useful, say thank-you to the members of ArsTechnica forums (http://episteme.arstechnica.com/6/ubb.x).