To switch sound source from the command line: switchaudio Use this to make scripts such as: #!/bin/bash/Users/adam/humor/SwitchAudioSource -s "Built-in Line Output"afplay /Users/adam/humor/losinghorn.wav/Users/adam/humor/SwitchAudioSource -s "Built-in Output" Then make triggers in Quicksilver by:

1. Go to trigger pane, make new hotkey trigger
2. press "." to allow you to type a command
3. make sure the action is "Run"
4. hook up a hotkey
5. if it doesn't work, just try again. Persist through crashes, they happen often.

Follow-up: You can also control the volume! http://discussions.apple.com/thread.jspa?threadID=585781 `` osascript -e 'set volume output volume 100'``