I'm looking for a not applescript way to change the system volume on Mac OS X programmatically. I just couldn't find a solution. Anyone any ideas?
Take a look at this class:
https://github.com/InerziaSoft/ISSoundAdditions
It can change system volume and make use of CoreAudio API.
An example of usage should look like this:
[NSSound setSystemVolume:0.5]
来源：https://stackoverflow.com/questions/6278589/change-volume-on-mac-programmatically